Conservation of Angular Momentum

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,

• her moment of inertia increases and her angular speed decreases.
• her moment of inertia decreases and her angular speed increases.
• her moment of inertia increases and her angular speed increases.
• her moment of inertia increases and her angular speed remains the same.

A merry-go-round spins freely when Diego moves quickly to the center along a radius of the merry-go-round. As he does this, it is true to say that

• the moment of inertia of the system increases and the angular speed increases.
• the moment of inertia of the system decreases and the angular speed remains the same.
• the moment of inertia of the system decreases and the angular speed decreases.
• the moment of inertia of the system decreases and the angular speed increases.

The drive chain in a bicycle is applying a torque of 0.850 N ∙ m to the wheel of the bicycle. You can treat the wheel as a thin uniform hoop (or ring) with a mass of 0.750 kg and a radius of 33.0 cm. What is the angular acceleration of the wheel?

• 10.4 rad/s2
• 3.43 rad/s2
• 5.20 rad/s2
• 1.06 rad/s2

Tags

NGSS.HS-PS2-1

What does this formula measure?

• moment of inertia
• impulse
• electric current
• angular momentum

According to the Law of Conservation of Angular Momentum, if I (momentum of inertia) increases, what will happen to ω?

• Decrease
• Stay the same
• Increase

When a rigid object rotates about a fixed axis, what is true about all the points in the object? 

• They all have the same tangential acceleration.
• They all have the same angular speed.
• They all have the same tangential speed.
• They all have the same radial acceleration.

Two children, Ahmed and Saleh, ride on a merry-go-round. Ahmed is at a greater distance from the axis of rotation than Saleh. Which of the following are true statements? 

• Saleh and Ahmed have the same tangential speed.
• Ahmed has a greater tangential speed than Saleh.
• Saleh has a greater angular speed than Ahmed.
• Saleh has a smaller angular speed than Ahmed.

Which has greater angular speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

• The inside horse
• The outside horse
• Neither - they both have the same angular speed