Overview
Question 20
Consider a person with a mass of m who is in the space station with artificial gravity.
When he is in the occupied outer ring, his simulated weight in newtons is 1/2 mg = 361 N.
Suppose that he climbs to a position in one of the radial tunnels that leads to the center of the station.
Let R be his distance in meters from the center of the station.
Determine his simulated weight in his new position when R= (1/5)R. Answer 36.1N
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Question 18
An asteroid with mass m 6.47×109 kg comes from deep space, effectively from infinity, and falls toward Earth.
Find the change in potential energy when it reaches a point 5.07×108m from Earth's center, assuming it falls from rest at infinity.
Mass of Earth is M=5.96× 1024 kg, Earth's Radius is R=6,372km.
Use universal gravitational constant G=6.67×10-11 m3 kg-1 s-2
Calculate the speed (km/s) of the asteroid at that point.
Answer 1.25
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Question 28
An astronaut candidate with a mass of 65kg is tested in a centrifuge with a radius of 18.0 m.
The centrifuge rotates in the horizontal plane.
It starts from rest at time t = 0 and has a constant angular acceleration of 0.27rad/s2.
Determine the magnitude of the horizontal force exerted on him by the centrifuge (a) at t = 8s.
Answer 5,458.75
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Question 35
The 3kg, uniform, horizontal rod is seen from the side.
if d1=26cm and d2=137cm, what is the net gravitational torque about the point shown?
Answer: 16.65
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Question 32
If you lift the front wheel of a poorly maintained bicycle off the ground and then start it spinning at 1.34 rev/sec, friction in the bearings causes the wheel to stop in just 9s.
If the moment of inertia of the wheel about its axle is 1.57kg·m2, what is the magnitude of the frictional torque?
Answer 1.47
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Question 13
Two identical spring scales are each attached to a cord that is wrapped around a pulley, as shown.
The two pulleys have identical mass M=1.00kg and radius
.
However, Pulley A is a solid disk, whereas Pulley B has most of its mass located at its outer rim.
Both pulleys can rotate about their centers with negligible friction in their axles.
The pulleys are initially at rest when the two spring scales are pulled with the same constant force Fs=8N, causing both pulleys to rotate.
(Question for a thought: Predict which of the pulleys, if either, will complete one revolution first. Why?)
What will be the time (in seconds) it takes Pulley A to complete one revolution?
Let IA = ½MR2 and IB = MR2 be the pulley’s rotational inertias.
ANswer: .33