Answer:
Part a)
[tex]\frac{v_A}{v_B} = -\frac{m_B}{m_A}[/tex]
Part b)
[tex]\frac{K_A}{K_B} = \frac{m_B}{m_A}[/tex]
Explanation:
Part a)
As we know that initially the two blocks are connected by a spring and initially stretched by some amount
Since the two blocks are at rest initially so its initial momentum is zero
since there is no external force on this system so final momentum is also zero
[tex]m_Av_{1i} + m_Bv_{2i} = m_Av_A + m_Bv_B[/tex]
now for initial position the speed is zero
[tex]0 = m_Av_A + m_Bv_B[/tex]
now we have
[tex]\frac{v_A}{v_B} = -\frac{m_B}{m_A}[/tex]
Part b)
now for ratio of kinetic energy we know that the relation between kinetic energy and momentum is given as
[tex]K = \frac{P^2}{2m}[/tex]
now for the ratio of energy we have
[tex]\frac{K_A}{K_B} = \frac{P^2/2m_A}{P^2/2m_B}[/tex]
since we know that momentum of two blocks are equal in magnitude so we have
now we have
[tex]\frac{K_A}{K_B} = \frac{m_B}{m_A}[/tex]
Final answer:
To calculate the ratios of velocities and kinetic energies for two blocks connected by a massless spring released from rest, use conservation of momentum and the kinetic energy formula. The velocity ratio is mB/mA and the kinetic energy ratio is (mB/mA)².
Explanation:
The question is about two blocks connected by a massless spring on a frictionless surface. When they are released from rest after stretching the spring, we want to find the ratio of their velocities and kinetic energies during their motion.
Ratio of Velocities
The ratio of velocities is obtained through conservation of momentum. Since no external forces are involved and the spring does not have mass, the momentum of the system is conserved. Assuming block A and block B move in opposite directions after being released, their velocities will be in different directions but they will have the same magnitude of momentum.
Momentum conservation dictates that mAvA = mBvB, where vA and vB are their speeds respectively. Thus, the ratio of their velocities vA/vB = mB/mA.
Ratio of Kinetic Energies
The kinetic energy of each block is given by KE = (1/2)[tex]mv^2[/tex]. The ratio of their kinetic energies KEA/KEB is therefore [tex](m_Av_A^2)/(m_Bv_B2^)[/tex]. Inserting the ratios found in the velocities section, we find that the ratio of the kinetic energies is [tex](mB/mA)^2[/tex].
Calculate the heat flux (in W/m2) through a sheet of a metal 11-mm thick if the temperatures at the two faces are 350 and 110 ˚C. Assume steady-state heat flow and that the thermal conductivity of this metal is 53.0 W/m-K.
q = 1156363.6W/m².
To calculate the heat flux per unit area (W/m²) of a sheet made of metal:
q = -k(ΔT/Δx)
q = -k[(T₂ - T₁)/Δx]
Where, k is the thermal conductivity of the metal, ΔT is the temperature difference and Δx is the thick.
With Δx = 11 mm = 11x10⁻³m, T₂ = 350°C and T₁ = 110°C, and k = 53.0 W/m-K:
q = -53.0W/m-K[(110°C - 350°C)/11x10⁻³m
q = 1156363.6W/m²
Two cars approach an extremely icy four-way perpendicular intersection. Car A travels northward at 10 m/s and car B is traveling eastward. They collide and stick together, traveling at 41.5° north of east. What was the initial velocity of car B (in m/s)? (Enter the magnitude. Assume the masses of the cars are equal.)
Answer:
v = 11.3 m/s
Explanation:
Since there is no external force on the system of two cars
so here momentum of the system of two cars will remain constant
it is given here that two cars combined and move together at 41.5 degree North of East after collision
so here direction of final momentum is given as
[tex]tan\theta = \frac{P_y}{P_x}[/tex]
now we have initial momentum in the same direction
[tex]P_1 = m(10 m/s)\hat j[/tex]
[tex]P_2 = mv\hat i[/tex]
now we have
[tex]\frac{P_1}{P_2} = tan\theta[/tex]
[tex]\frac{m(10 m/s)}{mv} = tan41.5[/tex]
[tex]\frac{10}{v} = 0.88[/tex]
[tex]v = 11.3 m/s[/tex]
Using the principles of conservation of momentum and trigonometry, the initial velocity of car B can be calculated to be approximately 9.75 m/s.
Explanation:The problem can be solved using the principles of conservation of momentum. In a two-dimensional collision, the components of the momentum in the X and Y directions are separately conserved. Since we're given that the cars have equal mass and they stick together after colliding to make a single object, the magnitude of the velocity of the combined object after the collision must be equal to the vector sum of their initial velocities.
Car A is moving northward and thus its velocity is contributing only to the Y component of the total momentum. Car B, on the other hand, is moving eastward, so its velocity is contributing to the X component. When the cars collide and stick together, they move at an angle of 41.5° north of east, meaning there is both an X and Y component to their velocity.
Using trigonometry, the X component (eastward direction, i.e., car B's direction) can be found by VB = VA * tan(Θ). Given that VA is 10 m/s and Θ is 41.5 degrees, VB can be calculated to be approximately 9.75 m/s.
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A car is traveling at a speed of 70 mph, a long a straight road, when the driver slams on the brakes and the car m and the car a,=- 2.00 accelerates at comes to a complete stop. How much time passes between the time when the brakes were applied and the instant the car comes to a complete stop and how far did the car travel in that time? (1609 meters 1 mile, 3600 seconds 1 hour) a.) 7.28 s and 422.10 m. b.) 15.64 s and 244.70 m. c.) 12.32 s and 428.73 m. d.) 14.53 s and 210.98 m. e.) None of the above.
Answer:
Option B is the correct answer.
Explanation:
Speed of car = 70mph [tex]=70\times \frac{1609}{3600}=31.28m/s[/tex]
Deceleration of car = 2 m/s²
We have equation of motion
v = u + at
0 = 31.28 - 2 t
t = 15.64 seconds.
We also have
[tex]s=ut+\frac{1}{2}at^2=31.28\times 15.64-\frac{1}{2}\times 2\times 15.64^2=244.70m[/tex]
Option B is the correct answer.
A spider crawling across a table leaps onto a magazine blocking its path. The initial velocity of the spider is 0.870 m/s at an angle of 35.0° above the table, and it lands on the magazine 0.0770s after leaving the table. Ignore air resistance. How thick is the magazine? Express your answer in millimeters.
Answer:
Thickness of magazine = 9.42 mm.
Explanation:
Considering vertical motion of spider:-
Initial velocity, u = 0.870 sin 35 = 0.5 m/s
Acceleration , a = -9.81 m/s²
Time, t = 0.077 s
We have equation of motion s= ut + 0.5 at²
Substituting
s= 0.5 x 0.077 - 0.5 x 9.81 x 0.077²
s = 9.42 x 10⁻³ m = 9.42 mm
Thickness of magazine = 9.42 mm.
The thickness of the magazine is determined using the vertical component of the spider's initial velocity and kinematic equations for constant acceleration. By calculating and converting the vertical displacement to millimeters, we can find the thickness of the magazine the spider lands on.
Given that the initial velocity in the vertical direction (Vy) can be found using the formula Vy = V * sin(θ), where V is the initial velocity of the spider and θ is the angle of projection, we can calculate Vy = (0.870 m/s) * sin(35.0°).
The vertical displacement (y) can then be calculated using the kinematic equation for constant acceleration, y = Vy * t + (1/2) * g * t^2, where t is the time of flight, and g is the acceleration due to gravity (approximately -9.81 m/s^2). Since we want to find the displacement in the upward direction and the spider lands on the magazine after 0.0770 s, we are looking for the magnitude of y when the spider lands.
Substituting the values we have: y = (0.870 m/s) * sin(35.0°) * 0.0770 s + (0.5) * (-9.81 m/s^2) * (0.0770 s)^2. The negative sign in the acceleration term accounts for the direction of gravity, which is downwards. After calculating this expression, we convert the result from meters to millimeters (by multiplying by 1000) to obtain the thickness of the magazine.
A quantity of a gas has an absolute pressure of 400 kPa and an absolute temperature of 110 degrees kelvin. When the temperature of the gas is raised to 235 degrees kelvin, what is the new pressure of the gas? (Assume that there's no change in volume.) A. 854.46 kPa B. 510 kPa C. 3.636 kPa D. 1.702 kPa
Answer:
A) 854.46 kPa
Explanation:
P₁ = initial pressure of the gas = 400 kPa
P₂ = final pressure of the gas = ?
T₁ = initial temperature of the gas = 110 K
T₂ = final temperature of the gas = 235 K
Using the equation
[tex]\frac{P_{1}}{T_{1}}=\frac{P_{2}}{T_{2}}[/tex]
Inserting the values
[tex]\frac{400}{110}=\frac{P_{2}}{235}[/tex]
P₂ = 854.46 kPa
A 0.12-kg ball is moving at 6 m/s when it is hit by a bat, causing it to reverse direction and have a speed of 14 m/s. What is the change in the magnitude of the momentum of the ball? A. 0.39 kg*m/s B. 0.42 kg*m/s C. 1.3 kg*m/s D. 2.4 kg*m/s
Explanation:
0.05
momentum =Mv
then,
Mv=mv
v2=0.12*6/14
v2=0.05kgm/s
The change in the magnitude of the momentum of the ball is 2.4 kg·m/s.
Explanation:To calculate the change in the magnitude of the momentum of the ball, we need to find the initial momentum and the final momentum of the ball. Momentum is calculated by multiplying the mass of an object by its velocity. Let's start by calculating the initial momentum:
Initial momentum = mass × initial velocity
Final momentum = mass × final velocity
Change in momentum = final momentum - initial momentum
Plugging in the given values:
Initial momentum = 0.12 kg × 6 m/s
Final momentum = 0.12 kg × (-14 m/s) (since the ball changes direction)
Change in momentum = (-1.68 kg·m/s) - (0.72 kg·m/s) = -2.4 kg·m/s.
The change in the magnitude of the momentum of the ball is 2.4 kg·m/s. However, since the question is asking for the magnitude, we take the absolute value of the change in momentum, which is 2.4 kg·m/s.
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If a 54 kg sprinter can accelerate from a standing start to a speed of 10 m/s in 3 s, what average power is generated?
Answer:
Power, P = 600 watts
Explanation:
It is given that,
Mass of sprinter, m = 54 kg
Speed, v = 10 m/s
Time taken, t = 3 s
We need to find the average power generated. The work done divided by time taken is called power generated by the sprinter i.e.
[tex]P=\dfrac{W}{t}[/tex]
Work done is equal to the change in kinetic energy of the sprinter.
[tex]P=\dfrac{\dfrac{1}{2}mv^2}{t}[/tex]
[tex]P=\dfrac{\dfrac{1}{2}\times 54\ kg\times (10\ m/s)^2}{3\ s}[/tex]
P = 900 watts
So, the average power generated by the sprinter is 900 watts. Hence, this is the required solution.
Final answer:
The average power generated is 900 Watts, which is approximately 1.21 horsepower.
Explanation:
The question involves calculating the average power generated by a sprinter during acceleration. Power is defined as the work done per unit time. To find the power, we need to first calculate the work done, which, in the case of the sprinter, is the kinetic energy gained as they accelerate to the final speed.
In this case, we can calculate the kinetic energy (KE) of the sprinter using the formula KE = 0.5 × mass ×[tex]velocity^2[/tex]. The mass of the sprinter is given as 54 kg and the final velocity is 10 m/s. Thus, KE = 0.5 × 54 kg × [tex](10 m/s)^2[/tex] = 2700 Joules.
Now, the power can be found by dividing the work done by the time it takes to do that work. The sprinter takes 3 seconds to achieve this final velocity. So, the average power P is P = work/time = 2700 Joules / 3 s = 900 Watts.
Converting this power to horsepower (1 horsepower = 746 Watts), we get approximately P = 900 W × 1 hp/746 W = 1.21 horsepower.
An incandescent lightbulb emits 96 W of radiation. If the filanent is at a temperature of 3242 K, what is the area of the filament
Answer:
1.53 x 10^-5 m^2
Explanation:
use the Stefan's law
Energy per unit time = σ x A x T^4
σ = 5.67 x 10 -8 W/m^2 K^4
96 = 5.67 x 10^-8 x A x (3242)^4
A = 1.53 x 10^-5 m^2
By how much does a 64.3 kg mountain climber stretch her 0.910 cm diameter nylon rope when she hangs 32.2 m below a rock outcropping? (For nylon, Y = 1.35 â 10^9 Pa. Enter your answer in centimeters.)
Answer:
23 cm
Explanation:
m = 64.3 kg, diameter = 0.910 cm
radius, r = 0.455 cm = 4.55 x 10^-3 m
A = 3.14 x (4.55 x 10^-3)^2 = 6.5 x 10^-5 m^2
L = 32.2 m
Y = 1.35 x 10^9 Pa
Let the stretched length is l.
Use the formula for Young's modulus
Y = mg L / A l
l = m g L / A Y
l = (64.3 x 9.8 x 32.2) / (6.5 x 10^-5 x 1.35 x 10^9)
l = 0.23 m
l = 23 cm
At the instant a current of 0.40 A is flowing through a coil of wire, the energy stored in its magnetic field is 9.5 ✕ 10−3 J. What is the self-inductance of the coil (in H)?
Final answer:
The self-inductance of the coil is calculated using the energy stored in its magnetic field and the current flowing through it. By rearranging the formula W = (1/2) * L * I², the self-inductance L is found to be 0.11875 H.
Explanation:
To calculate the self-inductance of the coil, we can use the formula for the energy stored in the magnetic field of an inductor:
Energy (W) = (1/2) * L * I²
Where:
W is the energy stored in the magnetic field
L is the self-inductance of the coil
I is the current flowing through the coil
From the question, we're given that the energy (W) is 9.5 x 10⁻³ J, and the current (I) is 0.40 A. We can rearrange the formula to solve for L:
L = 2W / I²
Substitute the given values:
L = 2 * (9.5 x 10⁻³ J) / (0.40 A)²
L = 2 * (9.5 x 10⁻³ J) / (0.16 A²)
L = (19 x 10⁻³ J) / (0.16 A²)
L = 0.11875 H
Therefore, the self-inductance of the coil is 0.11875 H (henrys).
A tennis ball is shot vertically upward in an evacuated chamber inside a tower with an initial speed of 20.0 m/s at time t=0s. What is the magnitude of the acceleration of the ball when it is at its highest point?
Answer:
at the highest point of the path the acceleration of ball is same as acceleration due to gravity
Explanation:
At the highest point of the path of the ball the speed of the ball becomes zero as the acceleration due to gravity will decelerate the motion of ball due to which the speed of ball will keep on decreasing and finally it comes to rest
So here we will say that at the highest point of the path the speed of the ball comes to zero
now by the force diagram we can say that net force on the ball due to gravity is given by
[tex]F_g = mg[/tex]
now the acceleration of ball is given as
[tex]a = \frac{F_g}{m}[/tex]
[tex]a = \frac{mg}{m} = g[/tex]
so at the highest point of the path the acceleration of ball is same as acceleration due to gravity
Final answer:
The magnitude of the acceleration of a tennis ball at its highest point, in an evacuated chamber and under the influence of gravity alone, is 9.8 m/s². This remains constant regardless of the ball's position in its trajectory.
Explanation:
The question asks about the magnitude of the acceleration of a tennis ball at its highest point when it is shot vertically upward in an evacuated chamber with an initial speed. This scenario is governed by the principles of classical mechanics, specifically under the domain of gravity's influence on objects in motion. Regardless of whether the object is moving up or down or is at its peak height, the acceleration due to gravity on Earth remains constant.
Acceleration at the highest point, or at any point during its motion under gravity alone (assuming no air resistance), is -9.8 m/s2. It's essential to understand that the negative sign indicates the direction of acceleration, which is towards the center of the Earth but does not affect the magnitude of acceleration. Hence, the magnitude of acceleration is 9.8 m/s2, indicating that gravity is the only force acting on the ball throughout its trajectory.
A jet airplane with a 75.0 m wingspan is flying at 255 m/s. What emf is induced between the wing tips in V if the vertical component of the Earth's magnetic field is 3.00 x 10^-5 T?
Answer:
The emf is 0.574 volt.
Explanation:
Given that,
Magnetic field [tex]B =3.00\times10^{-5}\ T[/tex]
Length = 75.0 m
Velocity = 255 m/s
We need to calculate the emf
Using formula of emf
[tex]\epsilon=Blv[/tex]
Where, v = velocity
l = length
B = magnetic field
Put the value into the formula
[tex]\epsilon= 3.00\times10^{-5}\times75.0\times255[/tex]
[tex]\epsilon=0.574\ volt[/tex]
Hence, The emf is 0.574 volt.
The emf induced between the wingtips of a jet airplane flying at 255 m/s with a 75.0 m wingspan in Earth's magnetic field of strength 3.00 x 10^-5 T is 0.57 V. This is calculated using the formula for motional emf: E = Blv.
Explanation:To calculate the emf induced between the airplane wings due to Earth's magnetic field, we use the formula for motional emf: E = Blv, where B is the magnetic field strength, l is the length of the conductor moving through the field (in this case, the wingspan of the airplane), and v is the velocity of the conductor.
Substituting the given values into the formula we get:
E = (3.00 x 10^-5 T) * (75.0 m) * (255 m/s) = 0.57 V
This means that a 0.57 Volt emf is induced between the wingtips of the airplane due to the Earth's magnetic field. This is a direct application of Faraday's law of electromagnetic induction, which states that a changing magnetic field will induce an emf in a conductor.
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Motor oil, with a viscosity of 0.25 N ∙ s/m 2, is flowing through a tube that has a radius of 5.0 mm and is 25 cm long. The drop in pressure is 300 kPa. What is the volume of oil flowing through the tube per second?
Answer:
1.18 x 10^-3 m^3/s
Explanation:
η = 0.25 N s/m^2, radius, r = 5 mm = 0.005 m, l = 25 cm = 0.25 m
P = 300 kPa = 300,000 Pa, Volume of flow = ?
By use of Poiseuillie's equation
Volume of flow = π P r^4 / (8 η l)
Volume of flow = (3.14 x 300000 x 0.005^4) / (8 x 0.25 x 0.25)
Volume of flow = 1.18 x 10^-3 m^3/s
Using Poiseuille's Law for viscous flow, the volume of oil flowing through the tube per second is calculated to be 1.8 liters/sec.
Explanation:The volume of oil flowing through the tube per second can be calculated using Poiseuille's Law, which is an equation for viscous flow. This Law states that the flow rate of fluid through a pipe (Q) is directly proportional to the fourth power of the radius (r) of the tube, the pressure difference (ΔP) and inversely proportional to the viscosity (η) of the fluid, and the length (L) of the tube.
Using Poiseuille's Law, we have:
Q = (π/8) * (ΔP/r^4L) * η
By substituting the provided values:
Q = (π/8) * (300,000 Pa/(0.005 m)^4 * 0.25 m) * 0.25 N ∙ s/m^2
This yields: Q = 0.0018 m^3/s, or 1.8 liters/sec.
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A total of 600 C of charge passes through flashlight bulb in 0.500 hr. What is the average current? Give your answer in A.
The average current passing through a device is given by:
I = Q/Δt
I is the average current
Q is the amount of charge that has passed through the device
Δt is the amount of elapsed time
Given values:
Q = 600C
Δt = 0.500hr = 1800s
Plug in the values and solve for I:
I = 600/1800
I = 0.333A
The average current flowing in the flashlight bulb is 0.333 A
The given parameters:
quantity of the charge, Q = 600 C
time of the current flow, t = 0.5 hour
To find:
the average current, IThe average current is calculated from quantity of charge that flows in the given time period:
Q = It
where:
I is the average current
Q is the quantity of the charge
t is the time period
From the equation above, make the average current the subject of the formula:
[tex]I = \frac{Q}{t} \\\\I = \frac{600 \ C}{0.5 \ hr \times 3600 \ s} \\\\I = \frac{600 \ C}{1800 \ s} \\\\I = 0.333 \ A[/tex]
Thus, the average current is 0.333 A
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As a car increases velocity, does its kinetic energy or momentum increase faster? Explain.
Explanation:
The kinetic energy of an object is associated with its motion. Mathematically, it is given by :
[tex]E_k=\dfrac{1}{2}mv^2[/tex]........(1)
Where
m is the mass of the car
v is the velocity of the car
And the momentum of an object is equal to the product of mass and velocity i.e.
[tex]momentum(p)=mass(m)\times velocity(v)[/tex]..........(2)
From equation (1) and (2) it is clear that the kinetic energy and the momentum is directly proportional to the velocity of the object. As a car increases velocity, its kinetic energy or momentum increase faster.
Birds resting on high-voltage power lines are a common sight. The copper wire on which a bird stands is 2.3 cm in diameter and carries a current of 45 A. If the bird's feet are 3.9 cm apart, calculate the potential difference between its feet. (The resistivity of the wire is 1.7 10-8 Ω · m)
Explanation:
It is given that,
Diameter of the copper wire, d = 2.3 cm
Radius of copper wire, r = 1.15 cm = 0.0115 m
Distance between bird's feet, l = 3.9 cm = 0.039 m
The resistivity of the wire, [tex]\rho=1.7\times 10^{-8}\ \Omega-m[/tex]
We need to find the potential difference between bird's feet. The resistance of the wire is calculated by :
[tex]R=\rho\times \dfrac{l}{A}[/tex]
[tex]R=1.7\times 10^{-8}\ \Omega-m\times \dfrac{0.039\ m}{\pi(0.0115\ m)^2}[/tex]
R = 0.00000159 ohms
[tex]R=1.59\times 10^{-6}\ \Omega[/tex]
Let V is the potential difference between bird's feet. It can be calculated using Ohm's law as :
[tex]V=I\times R[/tex]
[tex]V=45\ A\times 1.59\times 10^{-6}\ \Omega[/tex]
V = 0.000071 volts
or
[tex]V=7.1\times 10^{-5}\ volts[/tex]
So, the potential difference between the bird's feet is [tex]7.1\times 10^{-5}\ volts[/tex]. Hence, this is the required solution.
Even with a large estimated resistance for the bird (say, R_bird = 1000 Ω), the potential difference (V_bird) would be very small (V_bird = 45 A * 1000 Ω ≈ 45000 V). However, in reality, most of the current will flow through the much lower resistance wire, making the actual potential difference between the bird's feet much closer to zero.
Calculation (for illustration purposes only):
Even though the potential difference is negligible, we can estimate its upper bound (worst-case scenario) by assuming all the current flows through the bird's body.
Wire Resistance:
Diameter (d) = 2.3 cm = 0.023 m
Radius (r) = d/2 = 0.0115 m
Wire length between feet (l) = 3.9 cm = 0.039 m
Resistivity (ρ) = 1.7 x 10^-8 Ω · m
Wire Resistance (R_wire) = ρ * (l / π * r^2) = (1.7 x 10^-8 Ω · m) * (0.039 m / (π * (0.0115 m)^2)) ≈ 4.2 x 10^-7 Ω (very small)
Assuming All Current Through Bird:
Current (I) = 45 A
Bird's Body Resistance (R_bird) = V_bird / I (Since we don't have V_bird, this is just a placeholder)
Total Circuit Resistance (ignoring wire resistance):
R_total = R_bird + R_wire ≈ R_bird (because R_wire is negligible)
Potential Difference Across Bird (upper bound):
V_bird = I * R_total = I * R_bird (since R_wire is negligible)
A bluebird has mass of 34 grams. It flies from the ground to the top of an 8.5-m tree. What is the change in the bluebird's gravitational potential energy as it flies to the top of the tree? 2800J 290J 2.8J 280J 0.29J
Answer:
Gravitational potential energy, PE = 2.8 J
Explanation:
It is given that,
Mass of the bluebird, m = 34 g = 0.034 kg
It flies from the ground to the top of an 8.5-m tree, h = 8.5 m
We need to find the change in the bluebird's gravitational potential energy as it flies to the top of the tree. It can be calculated as :
[tex]PE=m\times g\times h[/tex]
[tex]PE=0.034\ kg\times 9.8\ m/s^2\times 8.5\ m[/tex]
PE = 2.83 J
or
PE = 2.8 J
So, the gravitational potential energy as it flies to the top of the tree is 2.8 J. Hence, this is the required solution.
A wheel that was initially spinning is accelerated at a constant angular acceleration of 5.0 rad/s^2. After 8.0 s, the wheel is found to have made an angular displacement of 400 radians. (a) How fast was the wheel spinning initially? (b) What is the final angular velocity of the wheel?
Answer:
a) Initial angular speed = 30 rad/s
b) Final angular speed = 70 rad/s
Explanation:
a) We have equation of motion s = ut + 0.5at²
Here s = 400 radians
t = 8 s
a = 5 rad/s²
Substituting
400 = u x 8 + 0.5 x 5 x 8²
u = 30 rad/s
Initial angular speed = 30 rad/s
b) We have equation of motion v = u + at
Here u = 30 rad/s
t = 8 s
a = 5 rad/s²
Substituting
v = 30 + 5 x 8 = 70 rad/s
Final angular speed = 70 rad/s
A solenoid with n1 = 1200 turns/m and a current I1 = 2.5 A is filled with a paramagnetic material at a temperature T1 = 320 K. A second solenoid with n2 = 1000 turns/m and a current I2= 0.85 A is filled with the same paramagnetic material at a different temperature T2. The magnetizations are the same in both cases. What is the value of T2?
Answer:
[tex]T_2[/tex] = [tex]90.667K[/tex]
Explanation:
Given:
For the first solenoid
Number of turns, n₁ = 1200 turns/m
Current, I₁ = 2.5 A
Paramagnetic material temperature, T₁ = 320 K
Now for the second solenoid
Number of turns, n₂ = 1000 turns/m
Current, I₂ = 0.85 A
Paramagnetic material temperature = T₂
The magnetic flux (B) is given as
[tex]B=\frac{c\mu_onI}{T}[/tex]
where,
c = curie's constant
μ₀ = arithmetic constant
also it is given that the magnetization in both the cases are same
therefore the magnetic flux will also be equal
thus,
[tex]\frac{c\mu_on_1I_1}{T_1}[/tex] = [tex]\frac{c\mu_on_2I_2}{T_2}[/tex]
or
[tex]\frac{n_1I_1}{T_1}[/tex] = [tex]\frac{n_2I_2}{T_2}[/tex]
or
[tex]\frac{1200\times 2.5}{320}[/tex] = [tex]\frac{1000\times 0.85}{T_2}[/tex]
or
[tex]9.375[/tex] = [tex]\frac{850}{T_2}[/tex]
or
[tex]T_2[/tex] = [tex]\frac{850}{9.375}[/tex]
or
[tex]T_2[/tex] = [tex]90.667K[/tex]
Two slits are illuminated by a 602 nm light. The angle between the zeroth-order bright band at the center of the screen and the fourth-order bright band is 17.4 ◦ . If the screen is 138 cm from the double-slit, how far apart is this bright?
Answer:
y = 43.2 cm
Explanation:
As we know by the formula of diffraction we have
[tex]a sin\theta = N\lambda[/tex]
here we have
[tex]\theta = 17.4[/tex]
N = 4
[tex]\lambda = 602 nm[/tex]
now we have
[tex]a sin(17.4) = 4(602\times 10^{-9})[/tex]
[tex]a = 8.05 \times 10^{-6} m[/tex]
now the distance of screen is 138 cm
now we can say
[tex]\frac{y}{L} = tan\theta[/tex]
[tex]y = L tan(\theta)[/tex]
[tex]y = 138 tan(17.4) = 43.2 cm[/tex]
The temperature of a pot of water is 90.0 °C and the mass of the water is 112 g. A block with a mass of 21.0 g and a temperature of 20.0°C is dropped into the water. The final temperature of the water and the block is 88.3 °C. The specific heat of water is exactly 1 cal/g.°C. How much heat was lost by the water? O 1.90 x10^2 cal O 35.7 cal O 7650 cal O 1.70 cal How much heat was gained by the block? O 1430 cal O 190 x10^2 cal O 35.7 cal O 68.3 cal What is the specific heat of the block? O 0.133 cal/g.°C O 5.33 cal/g.°C O273000 cal/g.°C O0.0249 cal/g.°C
Answer:
1.90 x 10² cal
1.90 x 10² cal
0.133 cal/(g °C)
Explanation:
For water :
[tex]m_{w}[/tex] = mass of water = 112 g
[tex]c_{w}[/tex] = specific heat of water = 1 cal/(g °C)
[tex]T_{wi}[/tex] = initial temperature of water = 90.0 °C
[tex]T_{wf}[/tex] = final temperature of water = 88.3 °C
[tex]Q_{w}[/tex] = Heat lost by water
Heat lost by water is given as
[tex]Q_{w}= m_{w}c_{w}(T_{wi} - T_{wf})[/tex]
[tex]Q_{w}[/tex] = (112) (1) (90.0 - 88.3)
[tex]Q_{w}[/tex] = 1.90 x 10² cal
[tex]Q_{B}[/tex] = Heat gained by the block
As per conservation of energy
Heat gained by the block = Heat lost by water
[tex]Q_{B}[/tex] = [tex]Q_{w}[/tex]
[tex]Q_{B}[/tex] = 1.90 x 10² cal
For Block :
[tex]m_{B}[/tex] = mass of block = 21.0 g
[tex]c_{B}[/tex] = specific heat of block
[tex]T_{bi}[/tex] = initial temperature of block = 20.0 °C
[tex]T_{bf}[/tex] = final temperature of block = 88.3 °C
[tex]Q_{B}[/tex] = Heat gained by Block = 1.90 x 10² cal
Heat gained by water is given as
[tex]Q_{B}[/tex] = m_{B}c_{B}(T_{bf} - T_{bi})[/tex]
1.90 x 10² = (21.0) (88.3 - 20.0) c_{B}
c_{B} = 0.133 cal/(g °C)
An airplane is moving horizontally with a constant velocity of (+ 115 m/s) at altitude of 1050 m. The directions to the right and upward have been chosen as the positive directions. The plane releases a "care package' that falls to the ground along a curved trajectory. Ignoring air resistance, determine the time required for the package to hit the ground
Answer:
The time required for the package to hit the ground = 14.63 seconds.
Explanation:
Considering vertical motion of care package:-
Initial velocity, u = 0 m/s
Acceleration , a = 9.81 m/s²
Displacement, s = 1050 m
We have equation of motion s= ut + 0.5 at²
Substituting
s= ut + 0.5 at²
1050 = 0 x t + 0.5 x 9.81 x t²
t = 14.63 seconds
The time required for the package to hit the ground = 14.63 seconds.
To determine the time required for the care package to hit the ground, we can separate the vertical and horizontal components of the motion. By using the equation h = (1/2)gt^2 and plugging in the values h = 1050 m and g = 9.8 m/s^2, we find that it will take approximately 14.63 seconds for the care package to hit the ground.
Explanation:To determine the time required for the care package to hit the ground, we can separate the vertical and horizontal components of the motion. Since the horizontal velocity of the airplane does not change, it will not affect the time of flight. The vertical motion can be analyzed using the equation of motion for free fall, which is h = (1/2)gt^2, where h is the initial vertical displacement, g is the acceleration due to gravity, and t is the time of flight. In this case, the initial vertical displacement is 1050 meters and the acceleration due to gravity is approximately 9.8 m/s^2. Plugging these values into the equation, we can solve for t and find the time required for the care package to hit the ground.
By using the equation h = (1/2)gt^2 and plugging in the values h = 1050 m and g = 9.8 m/s^2, we have 1050 = (1/2)(9.8)t^2. Solving for t, we get t^2 = (1050) / (0.5)(9.8) = 214.29. Taking the square root of both sides, we find t ≈ 14.63 seconds. Therefore, it will take approximately 14.63 seconds for the care package to hit the ground.
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The velocity field of a steady flow is given as V=(U0+bx)i?b y j , where U0 and b are constant. Find the acceleration in the x- and y-directions if U0=1m/ s and b=0.3m .
Explanation:
The velocity field o a steady flow is given by :
[tex]V=(U_o+bx)i[/tex]
Where
U₀ and b are constant
We know that, the acceleration is given by :
[tex]a=\dfrac{dV}{dt}[/tex]
[tex]a=\dfrac{d((U_o+bx)i)}{dt}[/tex]
a = b i
a = 0.3 m/s²
So, acceleration corresponding to this velocity is 0.3 m/s². Hence, this is the required solution.
How many excess electrons must be distributed uniformly within the volume of an isolated plastic sphere 25.0 cm in diameter to produce an electric field of 1500 N/C just outside the surface of the sphere?
Answer:
Required charge [tex]q=2.6\times 10^{9}C[/tex].
[tex]n=1.622\times 10^{10}\ electrons[/tex]
Explanation:
Given:
Diameter of the isolated plastic sphere = 25.0 cm
Magnitude of the Electric field = 1500 N/C
now
Electric field (E) is given as:
[tex]E =\frac{kq}{r^2}[/tex]
where,
k = coulomb's constant = 9 × 10⁹ N
q = required charge
r = distance of the point from the charge where electric field is being measured
The value of r at the just outside of the sphere = [tex]\frac{25.0}{2}=12.5cm=0.125m[/tex]
thus, according to the given data
[tex]1500N/C=\frac{9\times 10^{9}N\times q}{(0.125m)^2}[/tex]
or
[tex]q=\frac{0.125^2\times 1500}{9\times 10^{9}}[/tex]
or
Required charge [tex]q=2.6\times 10^{9}C[/tex].
Now,
the number of electrons (n) required will be
[tex]n=\frac{required\ charge}{charge\ of\ electron}[/tex]
or
[tex]n=\frac{2.6\times 10^{-9}}{1.602\times 10^{-19}}[/tex]
or
[tex]n=1.622\times 10^{10}\ electrons[/tex]
To produce an electric field of 1500 N/C just outside the surface of the plastic sphere, approximately 337.5 nC of excess charge must be distributed uniformly within its volume.
Explanation:To produce an electric field just outside the surface of the sphere, the excess charge on the surface of the sphere should be uniformly distributed within its volume. The electric field just outside a uniformly charged sphere is given by:
E = k * q / r2
Where E is the electric field, k is the Coulomb constant [tex](9 * 109 N m2/C^2)[/tex] q is the charge, and r is the distance from the center of the sphere to the point outside the surface. In this case, E is given as 1500 N/C and r is half the diameter of the sphere (12.5 cm).
Substituting the values into the equation, we can solve for q:
[tex]1500 N/C = (9 * 109 N m2/C2) * q / (0.125 m)^2[/tex]
Solving for q, we find that the excess charge on the surface of the sphere should be approximately [tex]3.375 x 10-7 C,[/tex] or about 337.5 nC.
An electron enters a magnetic field of 0.66 T with a velocity perpendicular to the direction of the field. At what frequency does the electron traverse a circular path? ( m el = 9.11 × 10-31 kg, e = 1.60 × 10-19 C)
Answer:
1.85 x 10^10 cycles per second
Explanation:
B = 0.66 T, theta = 90 degree, q = 1.6 x 10^-19 C,
The time period of electron is given by
T = 2 π m / B q
Frequency is teh reciprocal of time period.
f = 1 /T
f = B q / (2 π m)
f = (0.66 x 1.6 x 10^-19) / (2 x 3.14 x 9.1 x 10^-31)
f = 1.85 x 10^10 cycles per second
A power P is required to do work W in a time interval T. What power is required to do work 3W in a time interval 5T? (a) 3P (b) 5P (c) 3P/5 (a) P (e) 5P/3
Answer:
(c) 3P/5
Explanation:
The formula to calculate the power is:
[tex]P=\frac{W}{T}[/tex]
where
W is the work done
T is the time required for the work to be done
In the second part of the problem, we have
Work done: 3W
Time interval: 5T
So the power required is
[tex]P=\frac{3W}{5T}=\frac{3}{5}\frac{W}{T}=\frac{3}{5}P[/tex]
What frequency must a sound wave have in air to have the same wavelength as a 750 Hz sound wave in a platinum bar? Vair = 340 m/s, Vpt = 2800 m/s,
Answer:
f = 91.1 Hz
Explanation:
As we know that it is given here that wavelength of sound in platinum is same as the wavelength of sound in air
so we can use the formula of wavelength in two mediums
[tex]\frac{speed}{frequency} = \frac{speed}{frequency}[/tex]
now it is given that
[tex]v_{air} = 340 m/s[/tex]
[tex]v_{pt} = 2800 m/s[/tex]
frequency of sound in platinum is 750 Hz
now frequency of sound in air = f
now from above formula
[tex]\frac{340}{f} = \frac{2800}{750}[/tex]
[tex]f = 91.1 Hz[/tex]
As you stand by the side of the road, a car approaches you at a constant speed, sounding its horn, and you hear a frequency of 76 Hz. After the car goes by, you hear a frequency of 65 Hz. What is the speed of the car? The speed of sound in the air is 343 m/s.
Answer:
26.8 m/s
Explanation:
[tex]v[/tex] = constant speed of the car
[tex]V[/tex] = speed of sound = 343 m/s
[tex]f[/tex] = actual frequency of the horn
[tex]f_{app}[/tex] = frequency heard as the car approach = 76 Hz
frequency heard as the car approach is given as
[tex]f_{app}=\frac{vf}{V - v}[/tex]
[tex]76 =\frac{vf}{343 - v}[/tex] eq-1
[tex]f_{rec}[/tex] = frequency heard as the car recedes = 65 Hz
frequency heard as the car goes away is given as
[tex]f_{rec}=\frac{vf}{V + v}[/tex]
[tex]65 =\frac{vf}{343 + v}[/tex] eq-2
dividing eq-1 by eq-2
[tex]\frac{76}{65}=\frac{343+v}{343-v}[/tex]
[tex]v[/tex] = 26.8 m/s
Final answer:
To determine the car's speed using the Doppler Effect, we calculate the difference in observed sound frequencies as the car approaches and moves away. Applying formulas for Doppler Effect calculations, the speed of the car comes out to be approximately 14.6 m/s.
Explanation:
The question revolves around the phenomenon known as the Doppler Effect, which is observed when a sound source moves relative to an observer. To calculate the speed v of the car, we use the Doppler Effect equations for sound frequencies heard when the source is moving towards and then away from the observer:
For the source approaching:
f' = f * ((v + vo) / (v - vs))
, where:
f' is the observed frequency when the source is approaching (76 Hz)
f is the original frequency emitted by the source
v is the speed of sound (343 m/s)
vo is the speed of the observer (0 m/s, since the observer is stationary)
vs is the speed of the source (the car's speed, what we are solving for)
For the source receding:
f'' = f * ((v - vo) / (v + vs))
, where:
f'' is the observed frequency when the source is receding (65 Hz)
To find the car's speed, we need to solve for vs in both equations. By eliminating f (since it's the same for both equations), we can solve for vs. Using these equations, we determine that the speed of the car is approximately 14.6 m/s.
A merry-go-round is spinning at a rate of 4.04.0 revolutions per minute. Cora is sitting 0.50.5 m from the center of the merry-go-round and Cameron is sitting right on the edge, 2.0 m from the center. What is the relationship between the rotational speeds of the two children?
Answer:
angular speed of both the children will be same
Explanation:
Rate of revolution of the merry go round is given as
f = 4.04 rev/min
so here we have
[tex]f = \frac{4.04}{60} =0.067 rev/s[/tex]
here we know that angular frequency is given as
[tex]\omega = 2\pi f[/tex]
[tex]\omega = 2\pi(0.067)[/tex]
[tex]\omega = 0.42 rad/s[/tex]
now this is the angular speed of the disc and this speed will remain same for all points lying on the disc
Angular speed do not depends on the distance from the center but it will be same for all positions of the disc
A table-top fan has radius of 0.5 m. It starts to rotate from rest to 800 rpm within 30 seconds. Determine: 1) the angular momentum 2) how many revolutions have it gone through after 2 minutes? 3) If the rotational inertia of each blade around the center is 0.3 kg.m^ 2, what is the magnitude of the torque provided by the motor of the fan, assuming no friction?
Answer:
Part a)
L = 25.13 kg m^2/s
Part b)
N = 3200 rev
Part c)
torque = 0.837 Nm
Explanation:
Part a)
As we know that angular frequency is given as
[tex]\omega = 2\pi f[/tex]
[tex]\omega = 2\pi(800/60)[/tex]
[tex]\omega = 83.77 rad/s[/tex]
now the angular momentum is given as
[tex]L = I\omega[/tex]
[tex]L = (0.3)(83.77)[/tex]
[tex]L = 25.13 kg m^2/s[/tex]
Part b)
angular acceleration of fan is given as
[tex]\alpha = 2\pi\frac{800/60}{30}[/tex]
[tex]\alpha = 2.79 rad/s^2[/tex]
total number of revolutions are
[tex]N = \frac{1}{4\pi}\alpha t^2[/tex]
[tex]N = \frac{1}{4\pi}(2.79)(120^2)[/tex]
[tex]N = 3200 rev[/tex]
Part c)
Torque is given as
[tex]\tau = I\alpha[/tex]
[tex]\tau = (0.30)(2.79) = 0.837 Nm[/tex]