ROTATIONAL MOTION

A non-uniform bar is suspended by two strings making angles of 36.9° and 53.1° with the vertical. What determines the location of its center of gravity?

• The length of the strings
• The color of the bar
• The temperature
• The balance of forces and torques

What role does symmetry play in the alignment of L and ω?

• It increases angular speed
• It reduces total mass
• It changes the direction of force
• It ensures that L and ω are parallel

When is the equation L = Iω valid for a rotating rigid body?

• For all rotating bodies
• When I is not constant
• Only for point masses
• When the body rotates about a fixed symmetric axis

When are the angular momentum vector L and the angular velocity vector ω parallel?

• Always
• Only in vacuum
• When mass is zero
• When rotation is about a fixed symmetric axis

Is the angular momentum of the two-particle system described in the previous question the same about any point in space?

• No
• Only about the midpoint
• Depends on the observer
• Yes