Answer:
427.392 kJ
Explanation:
m = Mass of gas = 4.5 kg
Initial temperature = 200 K
Final temperature = 360 K
R = Mass specific gas constant = 296.8 J/kgK
[tex]\gamma[/tex] = Specific heat ratio = 1.5
Work done for a polytropic process is given by
[tex]W=\frac{mR\Delta T}{1-\gamma}\\\Rightarrow W=\frac{4.5\times 296.8(360-200)}{1-1.5}\\\Rightarrow W=-427392\ J\\\Rightarrow W=-427.392\ kJ[/tex]
The work input during the process is -427.392 kJ
A satellite is put into an elliptical orbit around the Earth. When the satellite is at its perigee, its nearest point to the Earth, its height above the ground is hp = 229.0 km, and it is moving with a speed of up = 8.050 km/s. The gravitational constant G equals 6.67 x 10-11 mº.kg-1.5-2 and the mass of Earth equals 5.972 x 1024 kg. When the satellite reaches its apogee, at its farthest point from the Earth, what is its height ha above the ground? For this problem, choose gravitational potential energy of the satellite to be 0 at an infinite distance from Earth. km
Answer:
The height above the ground is 1279.51 km
Solution:
As per the question:
Height above the ground, [tex]h_{p} = 229.0\ km[/tex]
Speed of the satellite, [tex]v_{p} = 8.050\ km/s = 8050\ m/s[/tex]
Gravitational constant, [tex]G = 6.67\times 10^{- 11}\ m.kg[/tex]
Mass of the Earth, m = [tex]5.972\times 10^{24}\ kg[/tex]
Now,
The distance of the earth from the perigee is given by:
[tex]R_{p} = h_{p} + R_{E}[/tex]
where
[tex]R_{E} = 6371\ km[/tex]
[tex]R_{p} = 229.0 + 6371 = 6600\ km[/tex]
Now,
To calculate the distance of the earth from the earth from the apogee:
[tex]R_{A} = \frac{R_{p}}{\frac{2Gm}{v_{p}^{2}R_{p} - 1}}[/tex]
[tex]R_{A} = \frac{6600\times 1000}{\frac{2\times 6.67\times 10^{- 11}\times 5.972\times 10^{24}}{8050^{2}6600\times 1000 } - 1}}[/tex]
[tex]R_{A} = 7650.51\ km[/tex]
Height above the ground, [tex]h_{A} = R_{A} - R_{E} = 7650.51 - 6371 = 1279.51\ km[/tex]
Jack stands at rest on a skateboard. The mass of Jack and the skateboard together is 75 kg. Ryan throws a 3.0 kg ball horizontally to the right at 4.0 m/s to Jack, who catches it. What is the initial momentum of the system in kg m/s?
Answer:
The initial momentum of the system is 12 kg m/s
Explanation:
Hi there!
The momentum of the system is calculated as the sum of the momenta of the objects that compose the system, in this case, Jack and the ball.
The momentum of each object is calculated as follows:
p = m · v
Where:
p = momentum
m = mass
v = velocity
The initial momentum of the system is the momentum before Jack catches the ball and is given by the sum of the momentum of the ball (pb) plus the momentum of Jack (pj) (let´s consider the right direction as positive):
Initial momentum = pb + pj
initial momentum = mb · vb + mj · vj
initial momentum = 3.0 kg · 4.0 m/s + 75 kg · 0 m/s
initial momentum = 12 kg m/s
The initial momentum of the system is 12 kg m/s
Final answer:
The initial momentum of the system, consisting of Jack, the skateboard, and the ball, is 0 kg m/s.
Explanation:
Initial momentum of the system:
To calculate the initial momentum of the system consisting of Jack, the skateboard, and the ball, we can use the principle of conservation of momentum. The initial momentum of the system is equal to the sum of the individual momenta of the objects involved.
Initial momentum = Total mass × Initial velocity = (75 kg + 3.0 kg) × 0 m/s = 0 kg m/s
The ratio of carbon-14 to nitrogen in an artifact is 1:1 . Given that the half-life of carbon-14 is 5730 years, how old is the artifact?
Answer: 5,728.5 years
Explanation:
By measuring the current ratio of daughter to parent, that is (Dt/Pt) one can deduce the age of any sample. The assumption is that there is no daughter atom present at time,t=0 and that the daughter atoms are due to the parent decay(where none has been lost).
Lamda= ln 2÷ half life,t(1/2)
Lamda= ln2= 0.693/5730 years
Lamda=1.21 × 10^-4
Using the formula below;
Age,t= 1/lamda× (ln {1+ Dt/Pt})------------------------------------------------------------------------------------(1)
Slotting our values into equation (1) above.
Age,t= 1/lamda(ln[1+1/1])
Age,t= 1/1.2×10^-4(ln 1+1)
Age,t= 1/1.21×10^-4(ln 2)
Age,t= ln 2/ 1.21×10^-4
Age, t= 5,728.5 years.
Answer:
11,460 years
Explanation:
half-life= 5,730 years
you are looking for the 1 from the ration 1:3
multiply the half-life by two in order to get the 1
5,730 x 2 = 11,640
=11,460 years
A 100 W incandescent lightbulb emits about 5 W of visible light. (The other 95 W are emitted as infrared radiation or lost as heat to the surroundings.) The average wavelength of the visible light is about 600 nm, so make the simplifying assumption that all the light has this wavelength. How many visible-light photons does the bulb emit per second?
The incandescent lightbulb emits approximately [tex]\(1.51 \times 10^{19}\)[/tex] visible-light photons per second.
To find the number of photons emitted per second, you can use the following steps:
1. Calculate the energy of one photon using the formula:
[tex]\[ E = hf \][/tex]
where:
- [tex]\( E \)[/tex] is the energy of one photon,
- [tex]\( h \)[/tex] is Planck's constant [tex](\( 6.626 \times 10^{-34} \ \text{Joule}\cdot\text{s} \))[/tex],
- [tex]\( f \)[/tex]is the frequency of the light.
The frequency [tex](\( f \))[/tex] can be determined using the speed of light [tex](\( c \))[/tex] and the wavelength [tex](\( \lambda \))[/tex]:
[tex]\[ f = \frac{c}{\lambda} \][/tex]
where:
- [tex]\( c \)[/tex] is the speed of light [tex](\( 3.00 \times 10^8 \ \text{m/s} \))[/tex],
- [tex]\( \lambda \)[/tex] is the wavelength of the light.
2. Find the number of photons emitted per second using the power of the visible light [tex](\( P_{\text{visible}} \))[/tex] and the energy of one photon:
[tex]\[ \text{Number of photons per second} = \frac{P_{\text{visible}}}{E} \][/tex]
where:
- [tex]\( P_{\text{visible}} \)[/tex] is the power of the visible light (5 W),
- [tex]\( E \)[/tex] is the energy of one photon.
Let's perform the calculations:
[tex]\[ f = \frac{c}{\lambda} \][/tex]
[tex]\[ f = \frac{3.00 \times 10^8 \ \text{m/s}}{600 \times 10^{-9} \ \text{m}} \][/tex]
[tex]\[ f = 5.00 \times 10^{14} \ \text{Hz} \][/tex]
Now, calculate the energy of one photon:
[tex]\[ E = hf \][/tex]
[tex]\[ E = (6.626 \times 10^{-34} \ \text{Joule}\cdot\text{s}) \times (5.00 \times 10^{14} \ \text{Hz}) \][/tex]
[tex]\[ E = 3.313 \times 10^{-19} \ \text{Joule} \][/tex]
Finally, calculate the number of photons emitted per second:
[tex]\[ \text{Number of photons per second} = \frac{5 \ \text{W}}{3.313 \times 10^{-19} \ \text{Joule/photon}} \][/tex]
[tex]\[ \text{Number of photons per second} \approx 1.51 \times 10^{19} \ \text{photons/s} \][/tex]
So, the incandescent lightbulb emits approximately [tex]\(1.51 \times 10^{19}\)[/tex] visible-light photons per second.
Consider the collision of a 1500-kg car traveling east at 20.0 m/s (44.7 mph) with a 2000-kg truck traveling north at 25 m/s (55.9 mph). The cars lock together in such a way as to prevent them from separating or rotating significantly. One second before the collision, the car is located at position (x,y) = (-20,0) m and the truck is located at position (x,y) = (0,-25) m.
1. Calculate the x-coordinate of the center of mass of the two-automobile system, xCM, one second before the collision. ________ m
2. Calculate the y-coordinate of the center of mass of the two-automobile system, xCM, one second before the collision.________ m
3. Calculate the magnitude of the velocity of the center of mass of the two-automobile system, vCM, one second before the collision. ________ m/s
4. Calculate the direction of the velocity of the center of mass of the two-automobile system, vCM one second before the collision. (Give you answer in degrees relative to the positive x-axis which points to the east.)
________ degrees
5. Calculate the magnitude of the velocity of the center of mass of the two-automobile system, vCM, immediately after the collision. ________ m/s
6. Calculate the direction of the velocity of the center of mass of the two-automobile system, vCM immediately after the collision. (Give you answer in degrees relative to the positive x-axis which points to the east.)
________ degrees
Answer:
1. [tex]X_{cm}=-8.57m[/tex]
2. [tex]Y_{cm}=-14.29m[/tex]
3. [tex]V_{cm} = 16.66m/s[/tex]
4. α = 59.05°
5. [tex]V_{cm} = 16.66m/s[/tex]
6. α = 59.05°
Explanation:
The position of the center of mass 1s before the collision is:
[tex]X_{cm}=\frac{X_c*mc+X_t*m_t}{m_c+m_t}[/tex]
where
[tex]X_c=-20m[/tex]; [tex]m_c=1500kg[/tex];
[tex]X_t=0m[/tex]; [tex]m_t=2000kg[/tex];
Replacing these values:
[tex]X_{cm}=-8.57m[/tex]
[tex]Y_{cm}=\frac{Y_c*mc+Y_t*m_t}{m_c+m_t}[/tex]
where
[tex]Y_c=0m[/tex]; [tex]m_c=1500kg[/tex];
[tex]Y_t=-25m[/tex]; [tex]m_t=2000kg[/tex];
Replacing these values:
[tex]Y_{cm}=-14.29m[/tex]
The velocity of their center of mass is:
[tex]V_{cm-x}=\frac{V_{c-x}*mc+V_{t-x}*m_t}{m_c+m_t}[/tex]
where
[tex]V_{c-x}=20m/s[/tex]; [tex]m_c=1500kg[/tex];
[tex]V_{t-x}=0m/s[/tex]; [tex]m_t=2000kg[/tex];
Replacing these values:
[tex]V_{cm-x}=8.57m/s[/tex]
[tex]V_{cm-y}=\frac{V_{c-y}*mc+V_{t-y}*m_t}{m_c+m_t}[/tex]
where
[tex]V_{c-y}=0m[/tex]; [tex]m_c=1500kg[/tex];
[tex]V_{t-y}=-25m[/tex]; [tex]m_t=2000kg[/tex];
Replacing these values:
[tex]V_{cm-y}=-14.29m[/tex]
So, the magnitude of the velocity is:
[tex]V_{cm}=\sqrt{V_{cm-x}^2+V_{cm-y}^2}[/tex]
[tex]V_{cm}=16.66m/s[/tex]
The angle of the velocity is:
[tex]\alpha =atan(V_{cm-y}/V_{cm-x})[/tex]
[tex]\alpha=59.05\°[/tex]
Since on any collision, the velocity of the center of mass is preserved, then the velocity after the collision is the same as the previously calculated value of 16.66m/s at 59.0° due north of east
Calculations using the physics concept of center of mass determine the positions and velocities of the system of two vehicles before and after collision. The x and y coordinates of the center of mass are found to be -12m and -15m respectively, with a combined vCM direction of 180 degrees relative to the positive x-axis.
Explanation:To answer the questions presented, it's important to recall the concept of center of mass in physics. The center of mass of a system of particles (like two cars in this case) is the point at which its mass may be considered to be concentrated, when calculating moments and linear momentum. The positions of center of mass are given by:
xCm = (m1*x1 + m2*x2) / (m1 + m2)
yCm = (m1*y1 + m2*y2) / (m1 + m2)
And the center of mass velocity can be found using:
vCm = (m1*v1 + m2*v2) / (m1 + m2)
Assuming east as positive x-direction and north as positive y-direction, substituting the given values into the equations above, we find that:
xCM is (-20 * 1500 + 0 * 2000) / (1500 + 2000) = -12 myCM is (0 * 1500 + -25 * 2000) / (1500 + 2000) = -15 mvCM is (20 * 1500 + 0 * 2000) / (1500 + 2000) = 12 m/sAnd since all motion is along the x and y axes, we can find the direction by calculating the arctangent of the ratio of the y-velocity to the x-velocity, yielding a vCM direction relative to the positive x-axis of 0 degrees. However, because the velocities are negative, the directions should be 180 degrees for xCM and 270 degrees for yCM. The combined direction would also be 180 degrees.Since the collision does not cause the vehicles to separate or rotate, vCM won't change and remains 12 m/s after the collision.Similarly, the direction of vCM won't change because the two cars are locked together.Learn more about Center of Mass here:https://brainly.com/question/33607198
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A Garden hose is attached to a water faucet on one end and a spray nozzle on the other end. The water faucet is turned on, but the nozzle is turned off so that no water flows through the hose. The hose lies horizontally on the ground, and a stream of water sprays vertically out of a small leak to a height of .68m. What is the pressure inside the hose?
Answer:
The gauge pressure is 6670.8 Pascal
Explanation:
Given the height is 0.68 m
The Gauge pressure is determine by the formula,
Gauge pressure , P = hdg
Where h = 0.68 m
d = 1000
g = 9.81
Substituting the values in the formula of Gauge pressure, we get
Gauge Pressure = hdg =[tex]0.68 \times 1000 \times 9.81[/tex]
Gauge Pressure = 6670.8
Therefore, the gauge pressure is 6670.8 Pascal
Two cars collide at an icy intersection and stick together afterward. The first car has a mass of 1800 kg and was approaching at 5.00 m/s due south. The second car has a mass of 700 kg and was approaching at 21.0 m/s due west. (a) Calculate the final velocity of the cars. (b) How much kinetic energy is lost in the collision? (This energy goes into deformation of the cars.)
Answer:
The final velocity of the cars is 6.894 m/s
The kinetic energy lost is 117,441 J
Explanation:
Using the conservation of the linear momentum :
[tex]P_i = P_f[/tex]
Where [tex]P_i[/tex] is the inicial linear momentum and [tex]P_f[/tex] is the final linear momemtum.
The linear momentum is calculated by:
[tex]P = MV[/tex]
where M is the mass and V is the velocity.
First we identify the directions of the velocity of both cars:
the first car is moving in the axis y for the south direction, we will take this direction like positive.the second car is moving in the axis x to the west, we will take this direction like positive.The conservation of the linear momentum is made on direction x, so:
[tex]P_i = P_f\\M_{1}V_{1ix} +M_{2}V_{2ix} = V_{sx}(M_1+M_2)[/tex]
where [tex]M_1[/tex] is the mass of the car 1, [tex]V_{1ix}[/tex] is the car 1's inicial velocity in the axis x, [tex]M_2[/tex] is the mass of the car 2, [tex]V_{2ix}[/tex] is the car 2's inicial velocity in the axis x and [tex]V_{sx}[/tex] is the velocity of the car 1 and car 2 after the collition.
The car 1 just move in the axis y so, it dont have horizontal velocity ([tex]V_{1ix}[/tex] = 0)
now the equation is:
[tex]M_2V_{2ix} = V_{sx}(M_1 +M_2)[/tex]
Replacing the values, we get:
(700 kg)(21 m/s) = [tex]V_{sx}[/tex]( 1800 kg + 700 kg)
solving for [tex]V_{sx}[/tex]:
[tex]V_{sx} = \frac{700(21)}{1800+700}[/tex]
[tex]V_{sx}[/tex] = 5.88 m/s
Now we do the conservation of the linear momentum on direction y:
[tex]P_i = P_f\\M_{1}V_{1iy} +M_{2}V_{2iy} = V_{sy}(M_1+M_2)[/tex]
where [tex]M_1[/tex] is the mass of the car 1, [tex]V_{1iy}[/tex] is the car 1's inicial velocity in the axis y, [tex]M_2[/tex] is the mass of the car 2, [tex]V_{2iy}[/tex] is the car 2's inicial velocity in the axis y and [tex]V_{sy}[/tex] is the velocity of the car 1 and car 2 together after the collition.
The car 2 just move in the axis x so, it don't have horizontal velocity ([tex]V_{2iy}[/tex] = 0)
now the equation is:
[tex]M_1V_{1iy} = V_{sy}(M_1 +M_2)[/tex]
Replacing the values, we get:
[tex]1800(5 m/s) = V_{sy}(1800 +700)[/tex]
solving for [tex]V_{sx}[/tex]:
[tex]V_{sy} = \frac{1800(5)}{1800+700}[/tex]
[tex]V_{sy}[/tex] = 3.6 m/s
Now, we have the two components of the velocity and using pythagorean theorem we find the answer as:
[tex]V_f = \sqrt{5.88^2+3.6^2}[/tex]
[tex]V_f =[/tex] 6.894 m/s
Finally we have to find the kinetic energy lost, so the kinetic energy is calculated by:
K = [tex]\frac{1}{2}MV^2[/tex]
so, ΔK = [tex]K_f -K_i[/tex]
where [tex]K_f[/tex] is the final kinetic energy and [tex]K_i[/tex] is the inicial kinetic energy.
then:
[tex]K_i = \frac{1}{2}(1800)(5)^2+\frac{1}{2}(700)(21)^2= 176,850 J[/tex]
[tex]K_f = \frac{1}{2}(1800+700)(6.894)^2 = 59,409 J[/tex]
so:
ΔK = 59409 - 176850 = -117441 J
Final answer:
The final velocity of the cars is -9.48 m/s due south. The amount of kinetic energy lost in the collision is 49275 J.
Explanation:
To find the final velocity of the cars, we can use the conservation of momentum principle. Since the cars stick together after the collision, their combined mass is 1800 kg + 700 kg = 2500 kg. We can calculate the momentum of each car before the collision and add them together. Car A's momentum is 1800 kg * (-5.00 m/s) = -9000 kg·m/s, and Car B's momentum is 700 kg * (-21.0 m/s) = -14700 kg·m/s. The combined momentum of the cars is -9000 kg·m/s + (-14700 kg·m/s) = -23700 kg·m/s. Since momentum is conserved, the combined momentum of the cars after the collision is also -23700 kg·m/s. Dividing this momentum by the combined mass of the cars gives us the final velocity: -23700 kg·m/s / 2500 kg = -9.48 m/s. The magnitude of the final velocity is 9.48 m/s, and the direction is south since Car A originally had a southward velocity.
To calculate the amount of kinetic energy lost in the collision, we need to find the initial and final kinetic energies. The initial kinetic energy is given by the formula KE = 0.5 * mass * velocity^2. For Car A, the initial kinetic energy is 0.5 * 1800 kg * (5.00 m/s)^2 = 11250 J. For Car B, the initial kinetic energy is 0.5 * 700 kg * (21.0 m/s)^2 = 51450 J. The total initial kinetic energy is 11250 J + 51450 J = 62700 J.
The final kinetic energy is given by the formula KE = 0.5 * mass * velocity^2. For the cars combined, the final kinetic energy is 0.5 * 2500 kg * (9.48 m/s)^2 = 111975 J.
The kinetic energy lost in the collision is the difference between the initial kinetic energy and the final kinetic energy, which is 62700 J - 111975 J = 49275 J.
Jupiter's moon Io has active volcanoes (in fact, it is the most volcanically active body in the solar system) that eject material as high as 500 km (or even higher) above the surface. Io has a mass of 8.93×1022 kg and a radius of 1821 km . For this calculation, ignore any variation in gravity over the 500-km range of the debris.
Final answer:
Io remains volcanically active due to tidal heating caused by Jupiter's gravitational forces.
Explanation:
Io, the innermost of Jupiter's Galilean moons, is known for its high level of volcanism, making it the most volcanically active body in the solar system. Despite its small size, Io remains volcanically active due to the effect of gravity, specifically tidal heating caused by the massive gravity of Jupiter. Jupiter's strong gravitational forces pull Io into an elongated shape, resulting in tidal heating that generates enough internal heat to drive volcanic activity on the moon.
A solid cylinder and a thin-walled hollow cylinder have the same radii. They are rolling horizontally toward the bottom of an incline. Assuming there is no friction, what is the maximum height each one reaches (in terms of the variables involved)?
Answer:
height solid / height hollow = 3/4
Explanation:
the height reached is directly proportional to the original KE of the object.
Total KE solid
=[tex]1/2mv^2+1/2\times1/2m r^2(v^2 / r^2 )=3/4mv^2[/tex]
Total KE hollow = [tex]1/2mv^2+1/2mr^2(v^2 / r^2 )=mv^2[/tex]
height solid / height hollow = 3/4
A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument?
Answer:
It's held together by the nuclear force.
Explanation:
There are more elemental forces than just the electromagnetic one. In this case, it is the nuclear force (called also strong force) the one that holds the nucleus together because it is stronger than the electromagnetic force over such short distances as the one inside the atomic nucleus.
Answer:
The strong nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together.
Explanation:
A 155 kg satellite is orbiting on a circular orbit 5995 km above the Earth's surface. Determine the speed of the satellite. (The mass of the Earth is 5.97×1024 kg, and the radius of the Earth is 6370 km.)
Answer:[tex]5.67\times 10^{3} m/s[/tex]
Explanation:
Given
mass of satellite [tex]m=155 kg[/tex]
Satellite is orbiting 5995 km above Earth surface
mass of Earth [tex]M=5.97\times 10^{24} kg[/tex]
Radius of Earth [tex]R=6370 km[/tex]
here [tex]r=R+5995=6370+5995=12,365 km[/tex]
Gravitational Force will Provide the centripetal Force
[tex]\frac{GMm}{r^2}=\frac{mv^2}{r}[/tex]
[tex]v=\sqrt{\frac{GM}{r}}[/tex]
[tex]v=\sqrt{\frac{6.67\times 10^{-11}\times 5.97\times 10^{24}}{12365\times 10^{3}}}[/tex]
[tex]v=\sqrt{32.203\times 10^6}[/tex]
[tex]v=5.67\times 10^3m/s=5674.7 km/s[/tex]
A conducting sphere of radius R carries positive charge q. Calculate the amount of work that would be required to move a small positive test charge q0 slowly from r=5R to r=3R. Assume that the presence of q0 has no effect on how the charge q is distributed over the sphere.
Express your answer in terms of the electric constant ϵ0 and some or all of the variables q, q0, and R.
The work done to move a positive test charge from a point at a radial distance of 5R from the center of a charged sphere to a point at a radial distance of 3R is given by the difference in the electric potentials at these points times the charge of the test charge.
Explanation:The work done, W, in moving a small positive test charge, q0, in an electric field produced by another charged object is given by the expression W = q0 x (Vf - Vi), where Vf and Vi are> the final and initial electric potentials, respectively. The electric potential, V, at a point located a distance r from the center of a conducting sphere carrying a charge q is V = 1/4πε0 x q/r. So, the work done to move the test charge from r = 5R to r = 3R is W = q0 x {[1/4πε0 x q/(3R)] - [1/4πε0 x q/(5R)]}, which simplifies to W = q0q/4πε0R x (5/15 - 3/25).
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The work required to move a small positive test charge from a radius of 5R to 3R on a conducting sphere of radius R carrying positive charge q is calculated to be W = q*q0/(30πϵ0R) using Coulomb's law and the work-energy theorem.
Explanation:The work needed to move a charge in an electric field is given by the integral of force times distance. The force on a charge in an electric field is given by Coulomb's law: F = k*q*q0/r^2, where k is Coulomb's constant = 1/4π*ϵ0. The work done in moving a charge from r1 to r2 is given by the integral from r1 to r2 of dr, which results in k*q*q0*(1/r1 - 1/r2).
In this case, with r1=5R and r2=3R, the work is W = k*q*q0*(1/5R - 1/3R), which simplifies to W = 2k*q*q0/(15R), or W = q*q0/(30πϵ0R) when substituting k = 1/4π*ϵ0.
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The uniform crate has a mass of 150 kg. The coefficient of static friction between the crate and the floor is μs = 0.2. The coefficient of static friction between the man's shoes and the floor is μ′s = 0.4. Assume the man only exerts a horizontal force on the crate. Determine whether the 85-kg man can move the crate.
Answer:
The man will be able to move the crate.
Explanation:
[tex]\mu_s[/tex] = Coefficient of static friction between the crate and the floor = 0.2
[tex]\mu'_s[/tex] = Coefficient of static friction between the man's shoes and the floor = 0.4
[tex]m_c[/tex] = Mass of crate = 150 kg
[tex]m_p[/tex] = Mass of man = 85 kg
g = Acceleration due to gravity = 9.81 m/s²
Horizontal force in order to move the crate is given by
[tex]F_h=\mu_sm_cg\\\Rightarrow F_h=0.2\times 150\times 9.81\\\Rightarrow F_h=294.3\ N[/tex]
Maximum force that the man can apply
[tex]F_m=\mu'_sm_pg\\\Rightarrow F_m=0.4\times 85\times 9.81\\\Rightarrow F_m=333.54\ N[/tex]
Here it can be seen that [tex]F_m>F_h[/tex].
So, the man will be able to move the crate.
Final answer:
To determine whether the 85-kg man can move the 150-kg crate, we need to compare the force of static friction between the crate and the floor with the force exerted by the man. If the force of static friction is greater than the force exerted by the man, the crate will not move. If it is less than or equal to the force exerted by the man, the crate will move.
Explanation:
The force of static friction can be calculated using the equation:
fs = μsN
where fs is the force of static friction, μs is the coefficient of static friction, and N is the normal force.
In this case, the normal force can be calculated as:
N = mass × gravity
where the mass is the total mass of the crate and the man, and gravity is the acceleration due to gravity.
If the force of static friction is greater than the force exerted by the man, the crate will not move. If the force of static friction is less than or equal to the force exerted by the man, the crate will move.
In this case, we have:
Mass of crate = 150 kg
Mass of man = 85 kg
Coefficient of static friction between crate and floor (μs) = 0.2
Coefficient of static friction between man's shoes and floor (μ's) = 0.4
Force exerted by man = mass of man × acceleration due to gravity
The normal force can be calculated as the sum of the weight of the crate and the weight of the man:
Normal force (N) = (mass of crate + mass of man) × acceleration due to gravity
The force of static friction between the crate and floor can be calculated as:
fs = μs × N
If this force is greater than the force exerted by the man, the crate will not move. If it is less than or equal to the force exerted by the man, the crate will move.
A heavy flywheel is accelerated (rotationally) by a motor that provides constant torque and therefore a constant angular acceleration α. The flywheel is assumed to be at rest at time t=0 in Parts A and B of this problem.
Part A
Find the time t1 it takes to accelerate the flywheel to ω1 if the angular acceleration is α.
Express your answer in terms of ω1 and α.
Part B
Find the angle θ1 through which the flywheel will have turned during the time it takes for it to accelerate from rest up to angular velocity ω1.
Express your answer in terms of some or all of the following:
A. ω1
B. α
C. t1.
Part C
Assume that the motor has accelerated the wheel up to an angular velocity ω1 with angular acceleration α in time t1. At this point, the motor is turned off and a brake is applied that decelerates the wheel with a constant angular acceleration of −5α. Find t2, the time it will take the wheel to stop after the brake is applied (that is, the time for the wheel to reach zero angular velocity).
Express your answer in terms of some or all of the following:
A. ω1
B. α,
C. t1.
Answer:
a)[tex]t_1=\frac{w_1-w_o}{\alpha}=\frac{w_1}{\alpha}sec[/tex]
b)[tex]\theta_1=\frac{w_1^2}{2\alpha}rad[/tex]
c)[tex]t_2=\frac{\alpha t_1}{5\alpha}=\frac{t_1}{5}sec[/tex]
Explanation:
1) Basic concepts
Angular displacement is defined as the angle changed by an object. The units are rad/s.
Angular velocity is defined as the rate of change of angular displacement respect to the change of time, given by this formula:
[tex]w=\frac{\Delat \theta}{\Delta t}[/tex]
Angular acceleration is the rate of change of the angular velocity respect to the time
[tex]\alpha=\frac{dw}{dt}[/tex]
2) Part a
We can define some notation
[tex]w_o=0\frac{rad}{s}[/tex],represent the initial angular velocity of the wheel
[tex]w_1=?\frac{rad}{s}[/tex], represent the final angular velocity of the wheel
[tex]\alpha[/tex], represent the angular acceleration of the flywheel
[tex]t_1[/tex] time taken in order to reach the final angular velocity
So we can apply this formula from kinematics:
[tex]w_1=w_o +\alpha t_1[/tex]
And solving for t1 we got:
[tex]t_1=\frac{w_1-w_o}{\alpha}=\frac{w_1}{\alpha}sec[/tex]
3) Part b
We can use other formula from kinematics in order to find the angular displacement, on this case the following:
[tex]\Delta \theta=wt+\frac{1}{2}\alpha t^2[/tex]
Replacing the values for our case we got:
[tex]\Delta \theta=w_o t+\frac{1}{2}\alpha t_1^2[/tex]
And we can replace [tex]t_1[/tex]from the result for part a, like this:
[tex]\theta_1-\theta_o=w_o t+\frac{1}{2}\alpha (\frac{w_1}{\alpha})^2[/tex]
Since [tex]\theta_o=0[/tex] and [tex]w_o=0[/tex] then we have:
[tex]\theta_1=\frac{1}{2}\alpha \frac{w_1^2}{\alpha^2}[/tex]
And simplifying:
[tex]\theta_1=\frac{w_1^2}{2\alpha}rad[/tex]
4) Part c
For this case we can assume that the angular acceleration in order to stop applied on the wheel is [tex]\alpha_1 =-5\alpha \frac{rad}{s}[/tex]
We have an initial angular velocity [tex]w_1[/tex], and since at the end stops we have that [tex]w_2 =0[/tex]
Assuming that [tex]t_2[/tex] represent the time in order to stop the wheel, we cna use the following formula
[tex]w_2 =w_1 +\alpha_1 t_2[/tex]
Since [tex]w_2=0[/tex] if we solve for [tex]t_2[/tex] we got
[tex]t_2=\frac{0-w_1}{\alpha_1}=\frac{-w_1}{-5\alpha}[/tex]
And from part a) we can see that [tex]w_1=\alpha t_1[/tex], and replacing into the last equation we got:
[tex]t_2=\frac{\alpha t_1}{5\alpha}=\frac{t_1}{5}sec[/tex]
The equation of motion for a simple harmonic oscillator (SHO) is:
m(d2x/ dt2) = −kx
where m is the mass and k the spring constant. A generic solution of the above differential equation can be written in the form:
x(t) = A cos(ωt + φ0).
Where ω = p k/m and A and φ0 are arbitrary constants to be determined by the initial conditions of the motion. You are given the following information: a block of mass m = 10 kg is attached to a spring with spring constant k = 2.5N/m; at time t = 0 the amplitude of the motion is 0, and the velocity is -5 m/s.
(a) Using the generic solution (1) above find the form x(t) for the position as a function of time for the block (you need to determine the constants A, ω and φ0). Do not forget to write clearly the appropriate dimension for each quantity, A, φ0, ω.
(b) Plot the function x(t) that you found in part (a) from t = 0 until t = 20s.
(You can use a graphical calculator or WolframAlpha or Desmos to make your plot)
Answer:
Explanation:
ω = [tex]\sqrt{\frac{k}{m} }[/tex]
k = 2.5 N/m
m = 10 kg
[tex]\omega = \sqrt{\frac{2.5}{10} }[/tex]
ω = .5 rad /s
x(t) = A cos(ωt + φ₀)
When t = 0 , x(t) = 0
0 = A cos(ωx 0 + φ₀)
cos φ₀ = 0
φ₀ = π /2
x(t) = A cos(ωt +π /2 )
Putting the value of ω
x(t) = A cos(.5 t +π /2 )
Differentiating on both sides
dx(t)/dt = - .5 A sin(.5 t +π /2 )
v(t) = - .5 A sin(.5 t +π /2 )
Given t =0 , v(t) = -5 m/s
-5 = - .5 A sin(.5 x0 +π /2 )
-5 = - .5 A sinπ /2
A = 10 m
x(t) = 10 cos( .5 t +π /2 )
b )
when t = π ( 3.14 s )
x(t) = - 10 m
when t = 2π ( 6.28s )
x(t) = 0
when t = 3π ( 9.42 s )
x(t) = 10 m
and so on
Final answer:
The position as a function of time for the block in the given scenario is x(t) = 0 for any value of t.
Explanation:
To find the form x(t) for the position as a function of time for the block in the given scenario, we first need to determine the constants A, ω, and φ0. We are given that at time t = 0, the amplitude of the motion is 0 and the velocity is -5 m/s.
Using the equation x(t) = A cos(ωt + φ0), we can determine the values of A, ω, and φ0. Since the amplitude is 0, we have A = 0. The velocity is given by v(t) = - Umax sin(ωt + φ0), where Umax = √(k/m)A. Plugging in the given velocity of -5 m/s, we can solve for Umax and find its value to be 5 m/s.
Using the equation ω = √(k/m), we can substitute in the given values to find ω. Therefore, ω = √(2.5 N/m /10 kg) = 0.5 rad/s. Finally, we can substitute the values of A = 0, ω = 0.5 rad/s, and φ0 = 0 into the equation x(t) = A cos(ωt + φ0) to find the form of x(t) as x(t) = 0 cos(0.5t + 0) = 0 for any value of t.
A mirror faces a cliff, located some distance away. Mounted onthe cliff is a second mirror, directly opposite the first mirrorand facing toward it. A gun is fired very close to the firstmirror. The speed of sound is 342 m/s.How many times does the flash of the gunshot travel the round-tripdistance between the mirrors before the echo of the gunshot isheard?
To develop this problem, we simply have to make a relationship between speeds. This is because the echo of the sound is traveling a distance equal to that which the light travels.
We must calculate how much is that relationship of round trips between the two, as well
[tex]N = \frac{c}{s}[/tex]
Where
c = Speed of light
s = Speed of sound
By definition we know that
[tex]c = 3*10^8m/s[/tex]
[tex]s = 342,2m/s[/tex](Normal conditions)
Then,
[tex]N = \frac{3*10^8m/s}{342,2m/s}[/tex]
[tex]N = 876680.3[/tex]
Therefore the flash of the gunshot travel the round-trip distance between the mirror around to 876680.3 times before the echo of the gunshot is heard.
To determine how many times the flash of the gunshot travels the round-trip distance between the mirrors before the echo is heard, we need to consider the time it takes for sound to travel from the gun to the first mirror, and then from the first mirror to the second mirror and back.
Explanation:To determine how many times the flash of the gunshot travels the round-trip distance between the mirrors before the echo is heard, we need to consider the time it takes for sound to travel from the gun to the first mirror, and then from the first mirror to the second mirror and back.
The total round-trip distance between the mirrors is twice the distance between the mirrors. Let's say this distance is 'd'.
The time it takes for sound to travel from the gun to the first mirror and back is given by 2d/v, where 'v' is the speed of sound.
So, the number of times the flash of the gunshot travels the round-trip distance before the echo is heard is given by the time taken for the sound divided by the time taken by the flash to travel the same distance.
Therefore, the answer to the question is the speed of sound divided by the speed of light (ignoring any delays due to the reflection in the mirrors).
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Two objects of the same size are both perfect blackbodies. One has a temperature of 3000 K, so its frequency of maximum emission is in the infrared region of the spectrum. The other has a temperature of 12,000 K, so its frequency of maximum emission is in the ultraviolet region of the spectrum.
Compared to the object at 3000 K, the object at 12,000 K:
A. emits more light in the infrared region of the spectrum.
B. emits more light in the visible region of the spectrum.
C. emits more light in the ultraviolet region of the spectrum
D. emits more light in only two of the three listed spectral regions.
E. emits more light in all three spectral regions.
The object at 12,000 K emits more light in the ultraviolet region of the spectrum compared to the object at 3000 K.
Explanation:When comparing the two objects, we can see that the object at 12,000 K emits more light in the ultraviolet region of the spectrum compared to the object at 3000 K. This is because as the temperature of an object increases, the frequency of maximum emission also increases. The object at 12,000 K has a higher frequency of maximum emission, which falls in the ultraviolet region of the spectrum.
When responding to sound, the human eardrum vibrates about its equilibrium position. Suppose an eardrum is vibrating with an amplitude of 5.70 10-7 m and a maximum speed of 2.66 10-3 m/s. (a) What is the frequency (in Hz) of the eardrum's vibration
Answer:
Frequency will be 743.09 Hz
Explanation:
We have given maximum speed [tex]v_m=2.66\times 10^{-3}m/sec[/tex]
Amplitude [tex]A=5.7\times 10^{-7}m[/tex]
We have to find the frequency of the vibration
We know that angular frequency is given by
[tex]\omega =\frac{v_m}{A}=\frac{2.66\times 10^{-3}}{5.7\times 10^{-7}}=4666.666rad/sec[/tex]
[tex]2\pi f=4666.66[/tex]
[tex]f=743.09Hz[/tex]
Two identical cars are driving in opposite directions at the same speed. Their kinetic energies have ____.
O the same magnitude, but opposite signs
O the same magnitude and sign
O different magnitudes, but the same sign
O different magnitudes and opposite signs
Answer:
Their kinetic energies have the same magnitude and sign.
Explanation:
Hi there!
Kinetic energy is not a vector, then it has no direction and therefore it does not matter the sense of movement of the car relative to a system of reference. Mathematically it would be also impossible to obtain a negative kinetic energy. The equation of kinetic energy (KE) is the following:
KE = 1/2 · m · v²
where m is the mass of the car (always positive) and v is its speed (not velocity, remember that the speed is the magnitude of the velocity vector, that´s why the kinetic energy is not a vector. I agree that the "v" in the formula is confusing).
So, even if we use a negative speed (that would be wrong), the kinetic energy will be positive because the speed is squared.
Then, if the cars have the same mass and speed, they will have the same kinetic energy, magnitude and sign (positive).
A 5.00-g bullet is shot through a 1.00-kg wood block suspended on a string 2.00 m long. The center of mass of the block rises a distance of 0.38 cm. Find the speed of the bullet as it emerges from the block if its initial speed is 450 m/s
Answer:395.6 m/s
Explanation:
Given
mass of bullet [tex]m=5 gm[/tex]
mass of wood block [tex]M=1 kg[/tex]
Length of string [tex]L=2 m[/tex]
Center of mass rises to an height of [tex]0.38 cm[/tex]
initial velocity of bullet [tex]u=450 m/s[/tex]
let [tex]v_1[/tex] and [tex]v_2[/tex] be the velocity of bullet and block after collision
Conserving momentum
[tex]mu=mv_1+Mv_2[/tex] -------------1
Now after the collision block rises to an height of 0.38 cm
Conserving Energy for block
kinetic energy of block at bottom=Gain in Potential Energy
[tex]\frac{Mv_2^2}{2}=Mgh_{cm}[/tex]
[tex]v_2=\sqrt{2gh_{cm}} [/tex]
[tex]v_2=\sqrt{2\times 9.8\times 0.38}[/tex]
[tex]v_2=0.272 m/s[/tex]
substitute the value of [tex]v_2[/tex] in equation 1
[tex]5\times 450=5\times v_1+1000\times 0.272[/tex]
[tex]v_1=395.6 m/s[/tex]
In simple harmonic motion, the speed is greatest at that point in the cycle whenA) the magnitude of the acceleration is a maximum.B) the displacement is a maximum.C) the magnitude of the acceleration is a minimum.D) the potential energy is a maximum.E) the kinetic energy is a minimum.
Answer:
C) the magnitude of the acceleration is a minimum.
Explanation:
As we know that ,the general equation of the simple harmonic motion given as
The displacement x given as
x=X sinω t
Then the velocity v will become
v= X ω cosωt
The acceleration a
a= - X ω² sinω t
The speed of the particle will be maximum when cosωt will become 1 unit.
It means that sinωt will become zero.So acceleration and displacement will be minimum.
Therefore when speed is maximum then acceleration will be minimum.
At the mean position the speed of the particle is maximum that is why kinetic energy also will be maximum and the potential energy will be minimum.
Therefore option C is correct.
In simple harmonic motion, the speed is greatest when the displacement is a maximum.
Explanation:In simple harmonic motion, the speed is greatest at the point in the cycle when the displacement is a maximum. When an object is at its maximum displacement, it has the maximum potential energy, and as it moves towards the equilibrium position, the potential energy is converted into kinetic energy, leading to an increase in speed.
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When light with a frequency f1 = 547.5 THz illuminates a metal surface, the most energetic photoelectrons have 1.260 x 10^-19 J of kinetic energy. When light with a frequency f2 = 738.8 THz is used instead, the most energetic photo-electrons have 2.480 x 10^-19 J of kinetic energy
Using these experimental results, determine the approximate value of Planck's constant.
Express your answer using four significant figures.
Answer:
[tex]h=6.377\times10^{-34}kgm^2/s[/tex]
Explanation:
The maximum kinetic energy of the photoelectrons is given by the formula [tex]K_M=hf-\phi[/tex].
We have two situations where for [tex]f_1=547.5\times10^{12}Hz[/tex] we get [tex]K_{M1}=1.26\times10^{-19}J[/tex] and for [tex]f_2=738.8\times10^{12}Hz[/tex] we get [tex]K_{M2}=2.48\times10^{-19}J[/tex], so we have:
[tex]K_{M1}=hf_1-\phi[/tex]
[tex]K_{M2}=hf_2-\phi[/tex]
We can eliminate [tex]\phi[/tex] by substracting the first equation to the second:
[tex]K_{M2}-K_{M1}=hf_2-\phi-(hf_1-\phi)=h(f_2-f_1)[/tex]
Which means:
[tex]h=\frac{K_{M2}-K_{M1}}{f_2-f_1}=\frac{2.48\times10^{-19}J-1.26\times10^{-19}J}{738.8\times10^{12}Hz-547.5\times10^{12}Hz}=6.377\times10^{-34}kgm^2/s[/tex]
Calculate the phase angle (in radians) for a circuit with a maximum voltage of 12 V and w-50 Hz. The voltage source is connected in series with a 20e-2 F capacitor, a 20-mH inductor, and a 50- resistor. -1.37 radians 0.134 radians 0.0180 radians 0.0300 radians
Answer:
The phase angle is 0.0180 rad.
(c) is correct option.
Explanation:
Given that,
Voltage = 12 V
Angular velocity = 50 Hz
Capacitance [tex]C= 20\times10^{-2}\ F[/tex]
Inductance [tex]L=20\times10^{-3}\ H[/tex]
Resistance [tex]R= 50\ Omega[/tex]
We need to calculate the impedance
Using formula of impedance
[tex]z=\sqrt{R^2+(\omega L-\dfrac{1}{\omega C})^2}[/tex]
[tex]z=\sqrt{50^2+(50\times20\times10^{-3}-\dfrac{1}{50\times20\times10^{-2}})^2}[/tex]
[tex]z=50.00[/tex]
We need to calculate the phase angle
Using formula of phase angle
[tex]\theta=\cos^{-1}(\dfrac{R}{z})[/tex]
[tex]\theta=\cos^{-1}(\dfrac{50}{50.00})[/tex]
[tex]\theta=0.0180\ rad[/tex]
Hence, The phase angle is 0.0180 rad.
A small, 0.10 kg cart is moving at 1.54 m/s when it collides with a larger 1.52 kg cart at rest. After the elastic collision, the small cart recoils (i.e. bounces off the larger cart and travels in the opposite direction) at a speed of 0.76 m/s.(a) What is the magnitude (absolute value) of the change in momentum for the small cart? kg m/s(b) What is the speed (absolute value of the velocity) of the larger cart after the collision? m/s
Answer:
a. the absolute value of the change in the momentum of the small car is 0.078
b. the velocity of the larger car after the collision is 0.1513 m/s
Explanation:
The linear momentum P is calculated as:
P = MV
Where M is the mass and V the velocity
Therefore, for calculated the change of the linear momentum of the small cart, we get:
[tex]P_{fc}-P_{ic} =[/tex]ΔP
where [tex]P_{ic}[/tex] in the inicial momentum and [tex]P_{fc}[/tex] is the final momentum of the small cart. Replacing the values, we get:
0.10 kg (0.76) -0.10(1.54) = -0.078 kg m/s
The absolute value: 0.078 kg m/s
On the other hand, using the law of the conservation of linear momentum, we get:
[tex]P_i = P_f[/tex]
Where [tex]P_i[/tex] is the linear momentum of the sistem before the collision and [tex]P_f[/tex] is the linear momentum after the collision.
[tex]P_i=P_{ic}\\P_f=P_{fc} + P_{ft}[/tex]
Where [tex]P_{fc}[/tex] is the linear momentum of the small cart after the collision and [tex]P_{ft}[/tex] is the linear momentum of the larger cart after the collision
so:
(0.10 kg)(1.54 m/s) = (0.10 kg)(-0.76 m/s) + (1.52 kg)(V)
Note: we choose the first direction of the small car as positive.
Solving for V:
[tex]\frac{0.10(1.54)+0.10(0.76)}{1.52} = V[/tex]
V = 0.1513 m/s
Final answer:
The magnitude of the change in momentum for the small cart is 0.078 kg·m/s. The speed of the larger cart after the collision is 0 m/s.
Explanation:
(a) What is the magnitude (absolute value) of the change in momentum for the small cart?
To find the change in momentum for the small cart, we can use the formula:
Change in momentum = mass × change in velocity
The mass of the small cart is 0.10 kg and its initial velocity is 1.54 m/s. After the collision, its velocity changes to -0.76 m/s (since it recoils in the opposite direction). Therefore, the change in velocity is: (0.76 m/s - 1.54 m/s) = -0.78 m/s.
Substituting the values into the formula, we get:
Change in momentum = 0.10 kg × (-0.78 m/s) = -0.078 kg·m/s
Since the question asks for the magnitude (absolute value) of the change in momentum, the answer is 0.078 kg·m/s.
(b) What is the speed (absolute value of the velocity) of the larger cart after the collision?
In an elastic collision, the total momentum before the collision is equal to the total momentum after the collision. Since the larger cart is initially at rest, its momentum before the collision is zero. Therefore, its momentum after the collision must also be zero.
Since momentum is equal to mass × velocity, the mass of the larger cart is 1.52 kg and its final velocity after the collision is denoted as Vf. We can set up the equation:
1.52 kg × Vf = 0 kg·m/s
Solving for Vf, we find that the velocity of the larger cart after the collision is also zero. Therefore, the answer is 0 m/s.
. In a physics lab, you attach a 0.200-kg air-track glider to the end of an ideal spring of negligible mass and start it oscillating. The elapsed time from when the glider first moves through the equilibrium point to the second time it moves through that point is 2.60 s. Find the spring’s force constant
The spring's force constant is [tex]\( 15.30 \, \text{N/m} \).[/tex]
To find the spring's force constant, we can use the formula for the period of oscillation of a mass-spring system:
[tex]\[ T = 2\pi \sqrt{\frac{m}{k}} \][/tex]
where [tex]\( T \)[/tex] is the period of oscillation, m is the mass attached to the spring, and [tex]\( k \)[/tex] is the spring constant.
Given:
[tex]\[ m = 0.200 \, \text{kg} \]\[ \text{Time for one complete oscillation } = 2.60 \, \text{s} \][/tex]
First, let's find the period [tex]\( T \)[/tex] using the given time for one complete oscillation:
[tex]\[ T = 2.60 \, \text{s} \][/tex]
Now, we can rearrange the formula for the period to solve for the spring constant [tex]\( k \):[/tex]
[tex]\[ k = \frac{4\pi^2 m}{T^2} \][/tex]
Substitute the known values:
[tex]\[ k = \frac{4\pi^2 \cdot 0.200 \, \text{kg}}{(2.60 \, \text{s})^2} \][/tex]
Calculate:
[tex]\[ k = \frac{4\pi^2 \cdot 0.200 \, \text{kg}}{6.76 \, \text{s}^2} \]\[ k = \frac{7.854 \, \text{kg} \cdot \text{m}^{-1}}{6.76 \, \text{s}^2} \]\[ k \approx 15.30 \, \text{N/m} \][/tex]
So, the spring's force constant is [tex]\( 15.30 \, \text{N/m} \).[/tex]
Complete Question:
In a physics lab, you attach a 0.200-kg air-track glider to the end of an ideal spring of negligible mass and start it oscillating. The elapsed time from when the glider first moves through the equilibrium point to the second time it moves through that point is 2.60 s. Find the spring’s force constant
A disc on a frictionless axle, starting from rest (0 rpm) can spin up to a rotation rate of 3820 rpm in a period of 2 seconds. (This is equivalent to angular acceleration of 200 rad/s.) Moment of inertia of disc = 5 kg-m. a) How much net torque was applied to the disc during the 2-s period? Answer: b) How much net torque would be needed to change the angular acceleration to 400 rad/s"? Answer: c) If the angular acceleration is 400 rad/s, how long will it take to spin up from 0 to 3820 rpm? Answer:
Answer:
1000 Nm
2000 Nm
1.00007 seconds
Explanation:
I = Moment of inertia = 5 kgm²
[tex]\alpha[/tex] = Angular acceleration
[tex]\omega_f[/tex] = Final angular velocity
[tex]\omega_i[/tex] = Initial angular velocity
t = Time taken
Torque is given by
[tex]\tau=I\alpha\\\Rightarrow \tau=5\times 200\\\Rightarrow \tau=1000\ Nm[/tex]
The torque of the disc would be 1000 Nm
If [tex]\alpha=400\ rad/s^2[/tex]
[tex]\tau=I\alpha\\\Rightarrow \tau=5\times 400\\\Rightarrow \tau=2000\ Nm[/tex]
The torque of the disc would be 2000 Nm
From equation of rotational motion
[tex]\omega_f=\omega_i+\alpha t\\\Rightarrow t=\frac{\omega_f-\omega_i}{\alpha}\\\Rightarrow t=\frac{3820\times \frac{2\pi}{60}-0}{400}\\\Rightarrow t=1.00007\ s[/tex]
It would take 1.00007 seconds to reach 3820 rpm
A major artery with a 1.6 cm2 cross-sectional area branches into 18 smaller arteries, each with an average cross-sectional area of 0.7 cm2. By what factor is the average velocity of the blood reduced when it passes into these branches?
To solve this problem it is necessary to apply the continuity equations for which it is defined that the proportion of Area in the initial section is equal to the final section. In other words,
[tex]A_1 v_1 = A_2 v_2[/tex]
Where,
[tex]A_i =[/tex] Cross sectional area at each section
[tex]v_i =[/tex]Velocities of fluid at each section
The total area of the branch is eighteen times of area of smaller artery. The average cross-sectional area of each artery is [tex]0.7cm^2.[/tex]
Therefore the Cross-sectional area at the end is
[tex]A_2= 18*0.7cm^2[/tex]
[tex]A_2 = 12.6cm^2[/tex]
Applying the previous equation we have then
[tex]A_1 v_1 = A_2 v_2[/tex]
[tex](1.7cm^2) v_1 = (12.6cm^2)v_2[/tex]
The ratio of the velocities then is
[tex]\frac{v_1}{v_2} = \frac{1.7}{12.6}[/tex]
[tex]\frac{v_1}{v_2} = 0.135[/tex]
Therefore the factor by which the velocity of blood will reduce when it enters the smaller arteries is 0.1349
A wire carries a current of 4.1 A. How many electrons per second are passing any cross sectional area of the wire? Enter your answer in the format *.**E** (for example, the fundamental unit of charge, which is 1.60 cross 10^(-19) C, would be entered by typing 1.60E-19). electrons per second
To solve this problem it is necessary to apply the concepts related to Current and Load.
The current in terms of the charge of an electron can be expressed as
[tex]i = \frac{q}{t}[/tex]
Where,
q = Charge
t = time
At the same time the Charge is the amount of electrons multiplied by the amount of these, that is
q = ne
Replacing in the first equation we have to
[tex]i = \frac{q}{t}[/tex]
[tex]i = \frac{ne}{t}[/tex]
Clearing n,
[tex]n = \frac{it}{e}[/tex]
Here the time is one second then
[tex]n = \frac{i}{e}[/tex]
[tex]n = \frac{4.1}{1.6*10^{-9}}[/tex]
[tex]n = 2.56*10^{19}electrons[/tex]
Therefore the number of electrons per second are passing any cross sectional area of the wire are [tex]2.56*10^{19}electrons[/tex]
How long must a simple pendulum be if it is to make exactly one swing per four seconds? (That is, one complete oscillation takes exactly 8.0 s.) Express your answer to two significant figures and include the appropriate units.
Answer:
Length of the pendulum will be 3.987 m
Explanation:
We have given time period of the pendulum T = 8 sec
Acceleration due to gravity [tex]g=9.81m/sec^2[/tex]
We have to find the length of the simple pendulum
We know that time period of the simple pendulum is given by
[tex]T=2\pi \sqrt{\frac{l}{g}}[/tex]
[tex]8=2\times 3.14 \sqrt{\frac{l}{9.81}}[/tex]
[tex]l=3.987m[/tex]
So length of the pendulum will be 3.987 m
A ball is dropped from the top of a tall building. At the same instant, a second ball is thrown upward from the ground level. When the two balls pass one another, one on the way up, the other on the way down, compare the magnitudes of their acceleration:
a. The acceleration changes during the motion, so you cannot predict the exact value when the two balls pass each other.
b. The acceleration of both balls is the same.
c. The acceleration of the ball thrown upward is greater.
d. The accelerations are in opposite directions.
e. The acceleration of the dropped ball is greater.
Answer:B
Explanation:
For the ball dropped From a tall ball building the direction of acceleration is downward and its magnitude is [tex]9.8 m/s^2[/tex]
For the ball thrown upward towards the dropped ball the direction and magnitude of acceleration is same i.e. downwards as gravity always acting downward with constant magnitude.
Thus option B is correct
In this case, the acceleration of both balls is the same (Option B).
What is acceleration?Acceleration is a physical property to measure the movement of an object in a given period of time.
Acceleration can be estimated as a change in velocity over the change in time (.e.g., meters per second squared).The conventionally used unit of measurement of the acceleration is meter per second squared.In conclusion, in this case, the acceleration of both balls is the same (Option B).
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