You are collecting data to study changes in the angular momentum of a bicycle wheel when a force is applied to it. Which of the following measurements would be least helpful to you?
the time for which the force is applied
the radius at which the force is applied
the angular velocity of the wheel when the force is applied
Which of the following would be the best way to produce measurable amounts of torque on a system to test the relationship between the angular momentum of the system, the average torque applied to the system, and the time for which the torque is applied?
having different numbers of people push on a merry-go-round
placing known masses on one end of a seesaw
touching the outer edge of a bicycle wheel to a treadmill that is moving at different speeds
hanging known masses from a string that is wound around a spool suspended horizontally on an axle
The diagram above shows a top view of a child of mass
M on a circular platform of mass 2
M that is rotating counterclockwise. Assume the platform rotates without friction. Which of the following describes an action by the child that will increase the angular speed of the platform-child system and why?
The child moves toward the center of the platform, increasing the total angular momentum of the system.
The child moves toward the center of the platform, decreasing the rotational inertia of the system.
The child moves away from the center of the platform, increasing the total angular momentum of the system.
The child moves away from the center of the platform, decreasing the rotational inertia of the system.
A moon is in an elliptical orbit about a planet as shown above. At point
A the moon has speed
uA and is at distance
RA from the planet. At point
B the moon has speed
uB . Has the moon's angular momentum changed? Explain your answer.
A hamster sits 0.10 m from the center of a lazy Susan of negligible mass. The wheel has an angular velocity of 1.0 rev/s. How will the angular velocity of the lazy Susan change if the hamster walks to 0.30 m from the center of rotation? Assume zero friction and no external torque.