ROTATIONAL MOTION

Why is the motion of the center of mass unaffected by internal forces during a collision?

• Collisions are too fast to affect motion
• The center of mass disappears temporarily
• Internal forces are negligible
• Internal forces cancel out due to Newton’s third law

What is the effect of external forces on the total momentum of a system of particles?

• They have no effect
• They only affect individual particles
• They always decrease momentum
• They can change the total momentum

How does an explosion in mid-air affect the total momentum of a projectile system?

• Momentum increases due to chemical energy
• Momentum is destroyed in the explosion
• Each fragment has zero momentum
• The total momentum remains unchanged if air resistance is neglected

What is the significance of Eq. (6.15), P = MV?

• It defines kinetic energy of the system
• It calculates gravitational force
• It describes rotational inertia
• It links the total momentum of a system to the motion of its center of mass

In the absence of external forces, how does the center of mass of a system move?

• It accelerates randomly
• It comes to rest
• It follows a circular path
• With constant velocity in a straight line