Answer:
Because of that but also because of its magnetic properties.
Explanation:
But its abundance in water and fat, since Magnetic Resonance Imaging uses our own body's magnetic properties to produce the images, and for this is much better to use something that is abundant in our own body and has magnetic properties, that is, and hydrogen nucleus ( single proton), being useful since it behaves like a small magnet.
Over a time interval of 1.99 years, the velocity of a planet orbiting a distant star reverses direction, changing from +20.7 km/s to -22.0 km/s. Find (a) the total change in the planet's velocity (in m/s) and (b) its average acceleration (in m/s2) during this interval. Include the correct algebraic sign with your answers to convey the directions of the velocity and the acceleration.
Answer:
(a) - 42700 m/s
(b) - 6.8 x 10^-4 m/s^2
Explanation:
initial velocity of star, u = 20.7 km/s
Final velocity of star, v = - 22 km/s
time, t = 1.99 years
Convert velocities into m/s and time into second
So, u = 20700 m / s
v = - 22000 m/s
t = 1.99 x 365.25 x 24 x 3600 = 62799624 second
(a) Change in planet's velocity = final velocity - initial velocity
= - 22000 - 20700 = - 42700 m/s
(b) Accelerate is defined as the rate of change of velocity.
Acceleration = change in velocity / time
= ( - 42700 ) / (62799624) = - 6.8 x 10^-4 m/s^2
A runner in a relay race runs 20 m north, turns around and runs south for 30 m, then turns north again and runs 40 m. The entire run took 30 seconds. What was the average speed of the runner? What was the average velocity of the runner?
Answer:
The average speed its 1 m/sThe average velocity its 1 m/s to the north.Explanation:
So, lets say the runner stars from the position [tex]x_0[/tex]. Lets make this point the origin of a coordinate system in which the vector i points north.
[tex]x_0 = (0,0)[/tex]
Now, in the first sections of the race, he runs 20 meters north, so, he finds himself at:
[tex]x_1 = x_0 + 20 m * i = (0,0) \ + (20 \ m,0)[/tex].
[tex]x_1 = (20 \ m,0)[/tex].
The, he runs 30 meters south
[tex]x_2 = x_1 - 30 \ m * i = (20 \ m,0)-(30 \ m,0)[/tex]
[tex]x_2 = (-10 \ m,0)[/tex]
Finally, he runs 40 meter north
[tex]x_3 = x_2 + 40 \ m * i = (-10 \ m,0)+(40 \ m,0)[/tex]
[tex]x_3 = (30 \ m,0)[/tex].
This is our displacement vector. Now, the average speed will be:
[tex]\frac{distance}{time}[/tex].
The distance its the length of the displacement vector,
[tex]d=\sqrt{x^2+y^2}[/tex]
[tex]d=\sqrt{(30 \ m)^2+0^2}[/tex]
[tex]d=30 \ m[/tex]
So, the average speed its:
[tex]\frac{30 \ m }{30 \ s} = 1\frac{m}{s}[/tex].
The average velocity, instead, its:
[tex]\vec{v} = \frac{displacement}{time}[/tex]
[tex]\vec{v} = \frac{(30 \ m ,\ 0)}{30 \ s}[/tex]
[tex]\vec{v} = (1 \ \frac{m}{s} ,\ 0)[/tex]
This is, 1 m/s north.
A crate of eggs is located in the middle of the flat bed of a pickup truck as the truck negotiates a curve in the flat road. The curve may be regarded as an arc of a circle of radius 36.1 m. If the coefficient of static friction between crate and truck is 0.570, how fast can the truck be moving without the crate sliding?
Answer:
[tex] v_{max}=14.2\frac{m}{s} [/tex]
Explanation:
Hi!
If the crate is not sliding, its trajectory is the arc with 36.1 m radius. Then the crate has a centripetal acceleration:
[tex]a_c= \frac{v^2}{r} \\r = radius\\v = tangential \; velocity[/tex]
The centripetal force acting on the crate is the static friction force between crate and truck. The maximum value of this force is:
[tex]F_{max} = \mu N\\\mu = 0.570=static\;friction \;coefficient\\N =normal\; force\\[/tex]
The normal force has a magnitude equal to the weight of the crate:
[tex]N=mg[/tex]
Then the condition for not sliding is:
[tex]F_{centripetal} = M\frac{v^2}{r}<\mu N=\mu Mg\\ v^2<r \mu g = 36.1\;m*0.570*9.8\frac{m}{s^2}= 201.65 \frac{m^2}{s^2}\\ v<14.2\frac{m}{s}[/tex]
At a construction site a pipe wrench struck the ground with a speed of 23 m/s. (a) From what height was it inadvertently dropped? (b)How long was it falling?
Answer:26.96 m,2.34 s
Explanation:
Given
Wrench hit the ground with a speed of 23 m/s
Applying equation of motion
[tex]v^2-u^2=2as[/tex]
Here u=0 because it is dropped from a height of S m
[tex]23^2-0=2\times 9.81\times s[/tex]
[tex]s=\frac{529}{2\times 9.81}=26.96 m[/tex]
Time required by wrench to hit the ground
v=u+at
[tex]23=9.81\times t[/tex]
[tex]t=\frac{23}{9.81}=2.34 s[/tex]
An insulated Thermos contains 134 g of water at 70.7°C. You put in a 13.8 g ice cube at 0.00°C to form a system of ice + original water. The specific heat of liquid water is 4190 J/kg*K; and the heat of fusion of water is 333 kJ/kg. What is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?
Answer:
[tex]\Delta s\ =\ 21.33\ J/K[/tex]
Explanation:
Given,
Mass of the ice = [tex]m_i\ =\ 13.8\ kg\ =\ 0.0138\ kg[/tex]Temperature of the ice = [tex]T_i\ =\ 0^o\ C[/tex]Mass of the original water = [tex]m_w\ =\ 134\ g\ =\ 0.134\ kg[/tex]Temperature of the original water = [tex]T_w\ =\ 70.0^o\ C[/tex]Specific heat of water = [tex]S_w\ =\ 4190\ J/kg K[/tex]Latent heat of fusion of ice = [tex]L_f\ =\ 333\ kJ/kg[/tex]Let T be the final temperature of the mixture,
Therefore From the law of mixing, heat loss by the water is equal to the heat gained by the ice,
[tex]m_iL_f\ +\ m_is_w(T_f\ -\ 0)\ =\ m_ws_w(T_w\ -\ T_f)\\\Rightarrow 333000\times 0.0138\ +\ 0.0138\times 4190T_f\ =\ 0.134\times 4190\times(70.7\ -\ T_f)\\\Rightarrow 4595.4\ +\ 57.96T_f\ =\ 39789.96\ -\ 562.8T_f\\\Rightarrow 620.76T_f\ =\ 35194.56\\\Rightarrow T_f\ =\ \dfrac{35194.56}{620.76}\\\Rightarrow T_f\ =\ 56.69^o\ C[/tex]
Now, We know that,
Change in the entropy,
[tex]\Delta s\ =\ s_f\ -\ s_i\ =\ \dfrac{Q}{T}\\\Rightarrow \displaystyle\int_{s_i}^{s_f} ds\ =\ \displaystyle\int_{T_i}^{T_f}\dfrac{msdT}{T}\\\Rightarrow \Delta s =\ ms \ln \left (\dfrac{T_i}{T_f}\ \right )\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,eqn (1)[/tex]
Now, change in entropy for the ice at 0^o\ C to convert into 0^o\ C water.
[tex]\Delta s_1\ =\ \dfrac{Q}{T}\\\Rightarrow \Delta s_1\ =\ \dfrac{m_iL_f}{T}\ =\ \dfrac{0.0138\times 333000}{273.15}\ =\ 16.82\ J/K.[/tex]
Change in entropy of the water converted from ice from [tex]273.15\ K[/tex] to water 330.11 K water.
From the equation (1),
[tex]\therefore \Delta s_2\ =\ ms \ln \left (\dfrac{T_i}{T_f}\ \right )\\\Rightarrow \Delta s_2\ =\ 0.0138\times 4190\times \ln \left (\dfrac{273.15}{330.11}\ \right )\\\Rightarrow \Delta s_2\ =\ 6.88\ J/K[/tex]
Change in entropy of the original water from the temperature 342.85 K to 330.11 K
From the equation (1),
[tex]\therefore \Delta s_3\ =\ ms \ln \left (\dfrac{T_i}{T_f}\ \right )\\\Rightarrow \Delta s_3\ =\ 0.134\times 4190\times \ln \left (\dfrac{330.11}{343.85} \right )\\\Rightarrow \Delta s_3\ =\ -2.36\ J/K[/tex]
Total entropy change = [tex]\Delta s\ =\ \Delta s_1\ +\ \Delta s_2\ +\ \Delta s_3\\\Rightarrow \Delta s\ =\ (16.82\ +\ 6.88\ -\ 2.36)\ J/K\\\Rightarrow \Delta s\ =\ 21.33\ J/K.[/tex]
Hence, the change in entropy of the system form then untill the system reaches the final temperature is 21.33 J/K
Three vectors →a, →b, and →c each have a magnitude of 50 m and lie in an xy plane. Their directions relative to the positive direction of the x axis are 30°, 195°, and 315°, respectively. What are (a) the magnitude and (b) the angle of the vector →a+→b+→c and (c) the magnitude and (d) the angle of →a−→b+→c? What are the (e) magnitude and (f) angle of a fourth vector →d such that (→a+→b)−(→c+→d)=0 ?
Answer:
(a): 37.94 m.
(b): [tex]323.16^\circ.[/tex]
(c): 126.957 m.
(d): [tex]0.93^\circ.[/tex]
(e): 49.92 m.
(f): [tex]130.08^\circ.[/tex]
Explanation:
Given:
Magnitude of [tex]\vec a[/tex] = 50 m.Direction of [tex]\vec a = 30^\circ.[/tex]Magnitude of [tex]\vec b[/tex] = 50 m.Direction of [tex]\vec b = 195^\circ.[/tex]Magnitude of [tex]\vec c[/tex] = 50 m.Direction of [tex]\vec c = 315^\circ.[/tex]Any vector [tex]\vec A[/tex], making an angle [tex]\theta[/tex] with respect to the positive x-axis, can be written in terms of its x and y components as follows:
[tex]\vec A = A\cos\theta\ \hat i+A\sin\theta \ \hat j.[/tex]
where, [tex]\hat i,\ \hat j[/tex] are the unit vectors along the x and y axes respectively.
Therefore, the given vectors can be written as
[tex]\vec a = 50\cos30^\circ \ \hat i+50\sin 30^\circ\ \hat j = 43.30\ \hat i +25\ \hat j\\\vec b = 50\cos195^\circ \ \hat i+50\sin 195^\circ\ \hat j = -48.29\ \hat i +-12.41\ \hat j\\\vec c = 50\cos 315^\circ \ \hat i+50\sin 315^\circ\ \hat j = 35.35\ \hat i +-35.35\ \hat j\\[/tex]
(a):
[tex]\vec a +\vec b + \vec c= (43.30\ \hat i +25\ \hat j)+(-48.29\ \hat i +-12.41\ \hat j)+(35.35\ \hat i +-35.35\ \hat j)\\=(43.30-48.29+35.35)\hat i+(25-12.41-35.35)\hat j\\=30.36\hat i-22.75\hat j.\\\\\text{Magnitude }=\sqrt{30.36^2+(-22.75)^2}=37.94\ m.[/tex]
(b):
Direction [tex]\theta[/tex] can be found as follows:
[tex]\tan\theta = \dfrac{\text{x component of }(\vec a + \vec b +\vec c)}{\text{y component of }(\vec a + \vec b +\vec c)}=\dfrac{-22.75}{30.36}=-0.749\\\Rightarrow \theta = \tan^{-1}(-0.749)=-36.84^\circ.[/tex]
The negative sign indicates that the sum of the vectors is [tex]36.84^\circ.[/tex] below the positive x axis.
Therefore, direction of this vector sum counterclockwise with respect to positive x-axis = [tex]360^\circ-36.84^\circ=323.16^\circ.[/tex]
(c):
[tex]\vec a -\vec b + \vec c= (43.30\ \hat i +25\ \hat j)-(-48.29\ \hat i +-12.41\ \hat j)+(35.35\ \hat i +-35.35\ \hat j)\\=(43.30+48.29+35.35)\hat i+(25+12.41-35.35)\hat j\\=126.94\hat i+2.06\hat j.\\\\\text{Magnitude }=\sqrt{126.94^2+2.06^2}=126.957\ m.[/tex]
(d):
Direction [tex]\theta[/tex] can be found as follows:
[tex]\tan\theta = \dfrac{\text{x component of }(\vec a - \vec b +\vec c)}{\text{y component of }(\vec a - \vec b +\vec c)}=\dfrac{2.06}{126.94}=0.01623\\\Rightarrow \theta = \tan^{-1}(0.01623)=0.93^\circ.[/tex]
(e):
[tex](\vec a + \vec b)-(\vec c + \vec d)=0\\(\vec a + \vec b)=(\vec c + \vec d)\\\vec d = \vec a + \vec b -\vec c.[/tex]
[tex]\vec d = \vec a +\vec b - \vec c= (43.30\ \hat i +25\ \hat j)+(-48.29\ \hat i +-12.41\ \hat j)-(35.35\ \hat i +-35.35\ \hat j)\\=(43.30-48.29-35.35)\hat i+(25-12.41+35.35)\hat j\\=-40.34\hat i+47.94\hat j.\\\\\text{Magnitude }=\sqrt{(-40.34)^2+47.94^2}=62.65\ m.[/tex]
(f):
Direction [tex]\theta[/tex] can be found as follows:
[tex]\tan\theta = \dfrac{\text{x component of }\vec d}{\text{y component of }\vec d}=\dfrac{47.94}{-40.34}=-1.188\\\Rightarrow \theta = \tan^{-1}(-1.188)=-49.92^\circ.[/tex]
The x component of this vector is negative and y component is positive therefore the vector lie in second quadrant, which means, the direction of this vector, counterclockwise with respect to positive x axis = [tex]180^\cir.
c-49.92^\circ=130.08^\circ.[/tex]
A delivery truck starts it’s run by driving 5.20 km due west before turning due north and driving an additional 2.10 km. Finally, the truck turns 30.0 degrees north of east and drives for 3.70 km before reaching its first dropoff point. What is the magnitude of the total displacement of the truck from where it started to its first dropoff point?
Answer:
4.427 m
Explanation:
We shall consider east as + x- axes and north as + ve y- axes. .
We shall represent every displacement in vector form as follows
D₁ = 5.2 km due west = - 5.2 i
D₂ = 2.1 km due north = 2.1 j
D₃ = 3.7 km towards north east at 30 degree from east
= 3.7 cos30 i + 3.7 sin 30 j = 3.2 i + 1.85 j
Total displacement D = D₁ + D₂ +D₃ +D₄.
- 5.2 i + 2.1 j + 3.2 i + 1.85 j
= - 2 i + 3.95 j
Magnitude of D
D² = (2)² + (3.95)²
= 4 + 15.6025
D = 4.427 m
Air enters a heat exchanger at a rate of 5000 cubic feet per minute at a temperature of 55 °F and pressure of 14.7 psia. The air is heated by hot water flowing in the same exchanger at a rate of 11,200 pounds per hour with a decrease in temperature of 10 °F. At what temperature does the air leave the heat exchanger?
Answer:
75 °F
Explanation:
Air has a specific heat at constant pressure of:
Cpa = 0.24 BTU/(lbm*F)
The specific heat of water is:
Cpw = 1 BTU/(lbm*F)
The first law of thermodynamics:
Q = L + ΔU
The heat exchanger is running at a steady state, so ΔU = 0. Also does not perform or consume any work L = 0.
Then:
Q = 0.
We split the heat into the heat transferred by the air and the heat trnasferred by the water:
Qa + Qw = 0
Qa = -Qw
The heat exchanged by the air is
Qa = Ga * Cpa * (tfin - ti)
And the heat exchanged by the water is:
Qw = Gw * Cpw * Δt
Replacing:
Ga * Cpa * (tfin - ti) = -Gw * Cpw * Δt
tfin - ti = (-Gw * Cpw * Δt) / (Ga * Cpa)
tfin = (-Gw * Cpw * Δt) / (Ga * Cpa) + ti
The G terms are mass flows, however we have volume flow of air.
With the gas state equation we calculate the mass:
p * V = m * R * T
m = (p * V) / (R * T)
55 °F = 515 °R
The gas constant for air is R = 53.35 (ft*lb)/(lbm* °R)
14.7 psi = 2117 lb/ft^2
m = (2117 * 5000) / (53.35 * 515) = 385 lbm
The mass flow is that much amount per minute
The mass flow of water is
11200 lbm/h = 186.7 lbm/min
Then:
tfin = (-186.7 * 1 * (-10)) / (385 * 0.24) + 55 = 75 °F
A body moving at .500c with respect to an observer
disintigratesinto two fragments
that move in opposite directions relative to their center
ofmass along the same line of motion as the original body.
Onefragment has a velocity of .600c in the backward direction
relativeto the center of mass and the other has a velocity of .500c
in theforward direction. What velocities will the observer
find?
Answer:
0.8c and -0.14c
Explanation:
The first fragment will have a speed of +0.5c respect of a frame of reference moving at +0.5c
Lest name v the velocity of the frame of reference, and u' the velocity of the object respect of this moving frame of reference.
The Lorentz transform for velocity is:
u = (u' + v) / (1 + (u' * v) / c^2)
u = (0.5c + 0.5c) / (1 + (0.5c * 0.5c) / c^2) = 0.8c
The other fragment has a velocity of u' = -0.6c respect of the moving frame of reference.
u = (-0.6v + 0.5c) / (1 + (0.5c * 0.5c) / c^2) = -0.14c
The question ask:
A block is hung by a string from the inside roof of a van.When
the van goes straight ahead at a speed of 28m/s, theblock hangs
vertically down. But when the van maintains this samespeed around
an unbanked curve (radius=150m), the block swingstoward the outside
of the curve. Then the string makes anangle theta with the
vertical. Find theta.
Answer:
[tex]\theta=28.07^{\circ}[/tex]
Explanation:
Speed of van, v = 28 m/s
Radius of unbanked curve, r = 150 m
Let [tex]\theta[/tex] is the angle with the vertical. In case of banking of road,
[tex]T\ cos\theta=mg[/tex].............(1)
And
[tex]T\ sin\theta=\dfrac{mv^2}{r}[/tex]..........(2)
From equation (1) and (2) :
[tex]tan\theta=\dfrac{v^2}{rg}[/tex]
[tex]tan\theta=\dfrac{(28)^2}{150\times 9.8}[/tex]
[tex]\theta=28.07^{\circ}[/tex]
So, the string makes an angle of 28.07 degrees with the vertical. Hence, this is the required solution.
An antelope moving with constant acceleration covers the distance 70.0 m between two points in time 6.60 s. Its speed as it passes the second point is 14.3 m/s. Part A
What is its speed at the first point?
Express your answer with the appropriate units. Part B
What is the acceleration?
Express your answer with the appropriate units.
Answer:
A) The speed at the first point is 6.91 m/s.
B) The acceleration is 1.12 m/s²
Explanation:
The equations of velocity and position of the antelope will be as follows:
x = x0 + v0 · t + 1/2 · a · t²
v = v0 + a · t
Where:
x = position of the antelope at time t
x0 = initial position
v0 = initial velocity
t = time
a = acceleration
v = velocity at time t
A) If we place the origin of the frame of reference at the first point, we can say that at t = 6.60 the position of the antelope is 70.0 m and its velocity is 14.3 m/s. In this way, we will have 2 equations with 2 unknowns, the initial velocity (the velocity at the first point) and the acceleration.
Let´s start finding the speed at the first point:
v = v0 + a · t (solving for "a")
(v - v0)/t = a
Replacing a = (v - v0)/t in the equation of the position:
x = x0 + v0 · t + 1/2 · (v - v0)/t · t² (x0 = 0)
x = v0 · t + 1/2 · v · t - 1/2 · v0 · t
x - 1/2 · v · t = 1/2 · v0 · t
2/t · (x - 1/2 · v · t) = v0
2/6.60 s · (70.0 m - 1/2 · 14.3 m/s · 6.60s) = v0
v0 = 6.91 m/s
The speed at the first point is 6.91 m/s.
B) Using the equation of velocity
a = (v - v0)/t
a = (14,3 m/s - 6.91 m/s) / 6.60 s
a = 1.12 m/s²
The acceleration is 1.12 m/s²
Our 12 V car battery does not appear to be functioning correctly, so we measure the voltage with a volt meter and find that the voltage on the battery is only 9V. To fix the problem, we connect the battery to a charger which delivers a constant current of i = 15 A. After t = 53 min on the charger, we find that voltage on the car battery is now 12.6V. Assuming that the voltage changed linearly during the charging process, how much energy was delivered to the car battery.
Answer:
507599.78 J
Explanation:
Charge input = current x time
=15 x 53 x 60
= 47000 coulomb
increase in voltage
= 12.6 - 9 = 3.6
capacity of the battery C = Charge input / increase in voltage
= 47000 / 3.6 = 13055.55
energy of the capacitor = 1/2 CV²
Initial energy of car battery = .5 x 13055.55 x 9 x 9
= 528749.77 J
Final energy of car battery
= .5 x 13055.55 x 12.6 x 12.6
= 1036349.55
Increase in energy = 507599.78 J
Final answer:
The total energy delivered to the car battery during its charging process from 9 V to 12.6 V over 53 minutes with a charging current of 15 A is 515,160 Joules.
Explanation:
To calculate the energy delivered to the car battery while it is being charged, we need to consider the change in voltage, the charge current, and the time it was charged. Since the voltage changed linearly from 9 V to 12.6 V over 53 minutes with a constant charging current of 15 A, we first convert the charging time to seconds (53 min imes 60 s/min = 3180 s) and then use the formula Energy (E) = Power (P) imes Time (t), where Power (P) is the product of voltage (V) and current (I).
Assuming a linear voltage increase, we take the average voltage (9 V + 12.6 V)/2 during the charge time. The average voltage is then 10.8 V. The energy delivered is given by:
E = P imes t = V imes I imes t = 10.8 V imes 15 A imes 3180 s
E = 515160 Joules
Therefore, the energy delivered to the car battery during the charging process is 515,160 Joules.
Two satellites, A and B are in different circular orbits
aboutthe earth. The orbital speed of satellite A is twice that
ofsatellite B. Find theratio (Ta/Tb) of the
periods ofthe satellites.
The ratio of the orbital periods (Ta/Tb) of two satellites, where the orbital speed of satellite A is twice that of satellite B, can be found using Kepler's third law, which relates the orbital period squared to the radius of the orbit cubed. By understanding the relationship between orbital speed and radius, the ratio of the orbital periods can be calculated.
Explanation:When comparing two satellites, A and B, with orbital speeds such that the orbital speed of satellite A is twice that of satellite B, we are tasked with finding the ratio of their orbital periods (Ta/Tb). This problem is grounded in the principles of classical mechanics and specifically relates to Kepler's laws of planetary motion.
According to Kepler's third law, the square of the orbital period (T) is proportional to the cube of the radius of the orbit (r). Mathematically, this is expressed as T² ≈ r³ for a satellite orbiting a much larger body, such as the Earth. Since the gravitational attraction provides the necessary centripetal force for the satellite's circular motion, the gravitational force is also centrally involved in this relationship.
To compare the periods of two satellites, we use this proportionality. If the orbital speed of satellite A is twice that of satellite B, the radius of the orbit is also related to the speed. Specifically, speed is directly related to the square root of the radius of the orbit based on centripetal force considerations. Since the speed of satellite A is twice that of satellite B (VA = 2*VB), it follows that the radius of A's orbit would be four times that of B's orbity (rA = 4*rB). Applying Kepler's law then allows us to find the period ratio as (Ta/Tb)² = (rA/rB)³, and after substituting the relation for the radii, we can solve for (Ta/Tb).
During the execution of a play, a football player carries the ball for a distance of 33 m in the direction 58° north of east. To determine the number of meters gained on the play, find the northward component of the ball's displacement.
Answer:28 m
Explanation:
Given
Direction is [tex]58^{\circ}[/tex] North of east i.e. [tex]58 ^{\circ}[/tex] with x axis
Also ball moved by 33 m
therefore its east component is 33cos58=17.48 m
Northward component [tex]=33sin58=27.98 m\approx 28 m[/tex]
Two students are sitting 1.50 m apart. One student has a mass of 70.0 kg and the other has a mass of 52.0 kg. What is the gravitational force between them?
Answer:
The gravitational force between them is [tex]1.079\times10^{-7}\ N[/tex].
Explanation:
Given that,
Distance = 1.50 m
Mass of one student = 70.0 kg
Mass of other student = 52.0 kg
We need to calculate the gravitational force
Using formula of gravitational force
[tex]F=\dfrac{Gm_{1}m_{2}}{r^2}[/tex]
Where, m₁ = mass of one student
m₂ = mass of other studen
r = distance between them
Put the value into the formula
[tex]F=\dfrac{6.67\times10^{-11}\times70.0\times52.0}{1.50^2}[/tex]
[tex]F=1.079\times10^{-7}\ N[/tex]
Hence, The gravitational force between them is [tex]1.079\times10^{-7}\ N[/tex].
To calculate the gravitational force between the two students, we use Newton's law of universal gravitation, substituting the given values for mass and distance into the formula. The result suggests that the gravitational force would be incredibly small, aligning with our daily experiences.
Explanation:The subject of this question is Physics, specifically gravitational force. From Newton's law of universal gravitation, we know that the gravitational force between two masses is given by the equation F = G(M₁M₂)/r², where F is the gravitational force, G is the gravitational constant, M₁ and M₂ are the two masses, and r is the distance between them.
Given that one student has a mass of 70 kg (M₁), the other a mass of 52 kg (M₂) and the distance between them is 1.5 m (r), we can substitute these values into the formula. Using a gravitational constant (G) of approximately 6.67 × 10-¹¹ Nm²/kg², the gravitational force (F) becomes:
F = (6.67 × 10-¹¹ Nm²/kg²)(70 kg)(52 kg)/(1.50 m)²
Note, though, that the gravitational force between two people sitting 1.50 m apart would be incredibly small due to the immense smallness of the gravitational constant. This is inline with our daily experiences where we don't feel any noticeable gravitational pull from an ordinary object.
Learn more about Gravitational Force here:https://brainly.com/question/32609171
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A ball is thrown with velocity of 10 m/s upwards. If the ball is caught 1 m above its initial position, what is the speed of the ball when it is caught?
Answer:
v = 8.96 m/s
Explanation:
Initial speed of the ball, u = 10 m/s
It caught 1 meter above its initial position.
Acceleration due to gravity, [tex]g=-9.8\ m/s^2[/tex]
We need to find the final speed of the ball when it is caught. Let is equal to v. To find the value of v, use third equation of motion as :
[tex]v^2-u^2=2as[/tex]
[tex]v^2=2as+u^2[/tex]
[tex]v^2=2(-9.8)\times 1+(10)^2[/tex]
v = 8.96 m/s
So, the speed of the ball when it is caught is 8.96 m/s. Hence, this is the required solution.
Answer:
8.96 m/s, upward direction
Explanation:
Given that, the initial velocity of the ball is,
[tex]u=10m/s[/tex]
And the acceleration in the downward direction is positive but in this situation the acceleration will be negative so,
[tex]a=9.8\frac{m}{s^{2} }[/tex]
And according to question vertical displacement is,
[tex]s=1m[/tex]
Now suppose v be the final velocity of the ball.
Applying third equation of motion,
[tex]v^{2}=u^{2}+2as[/tex]
Here, u is the initial velocity, a is the acceleration, s is the displacement.
Substitute all the variables.
[tex]v=\sqrt{10^{2}+2(-9.8)\times 1 } \\v=\sqrt{80.4}\\ v=8.96\frac{m}{s}[/tex]
Therefore, the speed of ball when it is caught is 8.96 m/s in the upward direction.
Consider an electron that is 10-10 m from an alpha particle (9 = 3.2 x 10-19 C). (Enter the magnitudes.) (a) What is the electric field in N/C) due to the alpha particle at the location of the electron? N/C (b) What is the electric field (in N/C) due to the electron at the location of the alpha particle? N/C (c) What is the electric force in N) on the alpha particle? On the electron? electric force on alpha particle electric force on electron
Answer:
a)[tex]E=2.88*10^{11}N/C[/tex]
b)[tex]E=1.44*10^{11}N/C[/tex]
c)[tex]F=4.61*10^{-8}N[/tex]
Explanation:
We use the definition of a electric field produced by a point charge:
[tex]E=k*q/r^2[/tex]
a)Electric Field due to the alpha particle:
[tex]E=k*q_{alpha}/r^2=9*10^9*3.2*10^{-19}/(10^{-10})^2=2.88*10^{11}N/C[/tex]
b)Electric Field due to electron:
[tex]E=k*q_{electron}/r^2=9*10^9*1.6*10^{-19}/(10^{-10})^2=1.44*10^{11}N/C[/tex]
c)Electric Force on the alpha particle, on the electron:
The alpha particle and electron feel the same force but with opposite direction:
[tex]F=k*q_{electron}*q_{alpha}/r^2=9*10^9*1.6*10^{-19}*3.2*10^{-19}/(10^{-10})^2=4.61*10^{-8}N[/tex]
A boy in a sleigh glides on a 40 angle snow-covered hill. The coefficient of kinetic friction between the surface and the sled is 0.12. The acceleration of the sled is: a. 3.6 m / s^2
b. 0.76 m / s^2
c. 2.3 m / s^2
d. 5.4 m / s^2
Answer:
option D
Explanation:
given,
angle of the snow-covering hill (θ) = 40°
coefficient of kinetic friction = 0.12
acceleration of the shed = ?
we know,
F = m a...................(1)
now,
[tex]F = m g sin\theta -\mu_k N sin\theta[/tex].......(2)
comparing equation (1) with (2)
[tex]m a =m g sin\theta -\mu_k m g sin\theta[/tex]
[tex]a = g sin \theta - \mu_k sin\theta[/tex]
[tex]a = 9.8\times sin 40^0 - 0.12\times 9.8\times sin40^0[/tex]
a = 5.54 m/s²
Hence, the correct answer is option D
A ball is thrown upward at time t=0 from the ground with an initial velocity of 4 m/s (~ 9 mph). Assume that g = 10 m/s^2. What is the greatest height (in meters) reached by the ball?
Answer:
The greatest height reached by the ball is 0.8 m.
Explanation:
Given that,
Initial velocity = 4 m/s
We need to calculate the greatest height reached by the ball
Using equation of motion
[tex]v^2=u^2+2gh[/tex]
Where, v = final velocity
u = initial velocity
g = acceleration due to gravity
Put the value in the equation
[tex]0=4^2+2\times(-10)\times h[/tex]
[tex]h =\dfrac{16}{20}[/tex]
[tex]h =0.8\ m[/tex]
Hence, The greatest height reached by the ball is 0.8 m.
A parallel-plate capacitor consists of two plates, each with an area of 27 cm^2 separated by 3.0 mm. The charge on the capacitor is 4.8 nC . A proton is released from rest next to the positive plate. How long does it take for the proton to reach the negative plate? Steps please with right answer.
Answer:
Explanation:
Capacity of a parallel plate capacitor C = ε₀ A/ d
ε₀ is permittivity whose value is 8.85 x 10⁻¹² , A is plate area and d is distance between plate.
C =( 8.85 X10⁻¹² X 27 X 10⁻⁴ ) / 3 X 10⁻³
= 79.65 X 10⁻¹³ F.
potential diff between plate = Charge / capacity
= 4.8 X 10⁻⁹ / 79.65 X 10⁻¹³
= 601 V
Electric field = V/d
= 601 / 3 x 10⁻³
= 2 x 10⁵ N/C
Force on proton
= charge x electric field
1.6 x 10⁻¹⁹ x 2 x 10⁵
= 3.2 x 10⁻¹⁴
Acceleration a = force / mass
= 3.2 x 10⁻¹⁴ / 1.67 x 10⁻²⁷
= 1.9 x 10¹³ m s⁻²
Distance travelled by proton = 3 x 10⁻³
3 x 10⁻³ = 1/2 a t²
t = [tex]\sqrt{\frac{3\times2\times10^{-3}}{1.9\times10^{13}} }[/tex]
t = 1.77 x 10⁻⁸ s
_______ activities give the teacher the opportunity to deliver instruction on a more personal level than _______ activities
A. Independent, holistic
B. Small group, kinesthetic
C. whole group, independent
D. Small group, whole group
Answer:
D. Small group, whole group
Explanation:
Small group activities give the teacher the opportinity to deliver instruction on a more personal level than whole group activities because in a smaller group there is more time to work with individuals as opposed to have to dedicate all time to generalized lessons for the whole group.
"The correct answer is D. Small group, whole group. Small group activities give the teacher the opportunity to deliver instruction on a more personal level than whole group activities
When comparing the types of activities listed, it is clear that small group activities allow for a more personal level of instruction compared to whole group activities. Small group activities involve fewer students, which means that the teacher can focus more on the individual needs of each student, provide more targeted feedback, and facilitate more in-depth discussions. This setting is conducive to addressing specific questions, adapting the pace of instruction to the group's needs, and fostering a sense of community among the students.
On the other hand, whole group activities involve the entire class and are less personal by nature. In this setting, the teacher must address a larger audience, which can make it challenging to meet every student's individual needs. Instruction is typically more general and may not be as tailored to each student's learning style or pace.
To contrast, independent activities do not involve direct instruction from the teacher, so they do not provide the opportunity for personal-level instruction. Kinesthetic activities involve movement and can be done individually or in groups, but they are not inherently more personal than small group activities. Therefore, the comparison between independent and holistic activities (A), or whole group and independent activities (C), does not accurately reflect the level of personalization in instruction.
Thus, the correct pair that illustrates the difference in the level of personalization in instruction is small group activities, which are more personal, compared to whole group activities, which are less personal."
A 5.0-V battery is places in series with two 1.25-Ω resistors. Determine the current through each resistor.
Answer:
Current through each resistor is 2 A.
Explanation:
Given that,
Voltage of a battery, V = 5 volts
Resistance 1, R = 1.25 ohms
Resistance 2,R' = 1.25 ohms
Both resistors are connected in series. The equivalent resistance is given by :
R" = R + R'
R" = 1.25 + 1.25
R" = 2.5 ohms
The current flowing throughout all resistors is same in series combination of resistors. Current can be calculated using Ohm's law as :
[tex]I=\dfrac{V}{R"}[/tex]
[tex]I=\dfrac{5\ V}{2.5}[/tex]
I = 2 A
So, the current through each resistor is 2 A. Hence, this is the required solution.
the wavelength of a certain light source is "0.535" where 1 micrometer = 1.0 x 10^-6m. express this wavelentg in nanometers.
Answer:
The answer is 535 nanometers.
Explanation:
[tex]1\ micrometer = 1\ \mu m = 1.0\times 10^{-6}\ m.[/tex]
and
[tex]1\ nanometer = 1\ nm = 1.0\times 10^{-9}\ m.[/tex],
so
[tex]1\ \mu m = 1.0 \times 10^{3}\ nm[/tex]
which means that
[tex]\lambda = 0.535\ \mu m = 535\ nm[/tex].
In fact we can say that the light is green, because its wavelength is in the range of 500 nm to 565 nm.
To find the velocity and acceleration vectors for uniform circular motion and to recognize that this acceleration is the centripetal acceleration. Suppose that a particle's position is given by the following expression: r(t)=R[cos(ωt)i^+sin(ωt)j^] =Rcos(ωt)i^+Rsin(ωt)j^.The particle's motion can be described by ____________.(A) an ellipse starting at time t=0 on the positive x axis(B) an ellipse starting at time t=0 on the positive y axis(C) a circle starting at time t=0 on the positive x axis(D) a circle starting at time t=0 on the positive y axis
Answer:
(C) a circle starting at time t=0 on the positive x axis
Explanation:
particle's position is
r(t)=R[cos(ωt)i^+sin(ωt)j^] =Rcos(ωt)i^+Rsin(ωt)j^
this is a parametric equation of a circle, because the axis at x and y are the same = R.
for t=0:
r=Ri^
so: circle starting at time t=0 on the positive x axis
On the other hand:
[tex]v=\frac{dx}{dt}= Rw[-sin(wt)i+cos(wt)j]\\a=\frac{dv}{dt}= Rw^{2}[-cos(wt)i-sin(wt)j][/tex]
The value of the magnitude of the acceleration is:
[tex]a=Rw^{2}(cos^{2}(wt)+sin^{2}(wt))=Rw^{2}[/tex]
we can recognise that this represent the centripetal acceleration.
You irradiate a crystalline sample that has 2.9344 Å between atoms with electrons to do an electron diffraction experiment in reflection mode. You observe a first order (m = 1) diffraction peak at θ = 12.062°. What is the wavelength of the electrons?
Answer:
[tex]\lambda=1.23[/tex]Å
Explanation:
Bragg's Law refers to the simple equation:
[tex]n\lambda = 2d sin(\theta)[/tex]
In this case:
n=1
θ = 12.062°
d=2.9344 Å
[tex]\lambda = 2*2.9344sin(12.062)=1.23[/tex]Å
You know that a point charge is located somewhere along the x-axis. When you measure the electric field at 2.00 m the result is 3.000 N/C and points left while the electric field at 5.00 m is 0.750 N/C also pointing left. (a) Where is the charge located?
(b) What is the size of the charge, including sign?
The electric field measurements indicate a point charge located to the right of both measurement positions on the x-axis, being more than 5.00 m away. Using the electric field values (3.000 N/C at 2.00 m and 0.750 N/C at 5.00 m), and applying the equation E = kQ/r^2, we can solve for both the point charge's magnitude and location.
The student's question revolves around the electric field produced by a point charge and involves finding both the location of the point charge and its magnitude. To solve this, we need to apply Coulomb's Law and the principle that the intensity of the electric field (E) from a point charge can be described by the equation E = kQ/r^2, where k is Coulomb's constant (8.988 imes 10^9 N m^2/C^2), Q is the charge, and r is the distance from the charge to the point where the electric field is measured.
Given the electric field measurements at two different points both pointing to the left, we can deduce that the point charge is located to the right of both points on the x-axis. The point charge must thus be more than 5.00 m to the right of the origin.
By using the measured electric field values and the distances to set up two equations, we can determine the charge's value:
E1 = kQ/r1^2 (at 2.00 m)
E2 = kQ/r2^2 (at 5.00 m)
Where E1 = 3.000 N/C, E2 = 0.750 N/C, r1 = 2.00 m, and r2 = 5.00 m. By solving these equations simultaneously, we can find the value of Q and the exact location along the x-axis.
Two 2.3 cm -diameter disks face each other, 2.9 mm apart. They are charged to ±16nC . A) What is the electric field strength between the disks?
Express your answer to two significant figures and include the appropriate units.
B) A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?
Express your answer to two significant figures and include the appropriate units.
Final answer:
To find the electric field strength between the disks, we can use Coulomb's law and the formula for electric field. The launch speed of the proton can be found using the conservation of energy.
Explanation:
To find the electric field strength between the disks, we can use the formula:
Electric Field = Force / Charge
The force between the disks is given by Coulomb's law:
Force = (k * q1 * q2) / r^2
Where k is the electrostatic constant (9 * 10^9 Nm^2/C^2), q1 and q2 are the charges on the disks, and r is the distance between them.
Substituting the given values, we have:
Force = (9 * 10^9 Nm^2/C^2) * (16 * 10^-9 C)^2 / (2.3 * 10^-2 m)^2
Calculating this expression, we get the force between the disks. Then, we can divide this force by the charge on either disk to find the electric field strength.
For part B, we can use the conservation of energy to find the launch speed of the proton. The potential energy difference between the disks can be calculated as:
Potential Energy = charge * voltage
Given the charge of the proton and the distance between the disks, we can find the voltage. Since the proton starts from rest, all of its initial potential energy will be converted into kinetic energy:
Kinetic Energy = (1/2) * mass * velocity^2
Where the mass of the proton is known.
Solving for velocity, we can find the launch speed of the proton.
A starship travels to a planet that is 20 light years away. The astronauts stay on the planet for 2.0 years before returning at the same speed and they are greeted back on earth 52 years after they left. Assume that the time needed to accelerate and decelerate is negligible. How much have the astronauts aged? (a) 15 years, (b) 20 years, (c) 22 years, (d) 30 years, (e) 32 years.
Answer:
astronauts age is 32 years
correct option is e 32 years
Explanation:
given data
travels = 20 light year
stay = 2 year
return = 52 years
to find out
astronauts aged
solution
we know here they stay 2 year so time taken in traveling is
time in traveling = ( 52 -2 ) = 50 year
so it mean 25 year in going and 25 years in return
and distance is given 20 light year
so speed will be
speed = distance / time
speed = 20 / 25 = 0.8 light year
so time is
time = [tex]\frac{t}{\sqrt{1-v^2} }[/tex]
time = [tex]\frac{25}{\sqrt{1-0.8^2} }[/tex]
time = 15 year
so age is 15 + 2 + 15
so astronauts age is 32 years
so correct option is e 32 years
How would you use the parallelogram method of vector addition when more than two forces are added?
Answer:
In order to use the parallelogram method, we have to select first two vectors. We move the vectors until their initial points coincide. Then we draw lines to form a complete parallelogram, as is shown in the figure annexed. The diagonal from the initial point to the opposite vertex of the parallelogram is the resultant.
We use the last vector resultant with a third vector, and we use again the parallelogram method to add them. We use the new resultant and we add it with a 4th vector. We repeat this task until all the vectors are used.
Many people believe that a vacuum created inside a
vacuumcleaner causes particles of dirt to be drawn in. Actually,
however,the dirt is pushed in. Explain.
Answer:Due to the pressure difference created by rotating fans.
Explanation:
In most of the vacuum cleaners, there is an area which is of disc shape and it is in right next to the motor. There are several fans within the disc that spin at a very high velocity.
The blades will push the air outside of the disk.There is no air in inside of the disc and air pressure creates which pushes air inside the disk to replace the missing air.
So motor is pushing the air outside and to maintain this pressure the air is pushing toward inside with dirt.