ROTATIONAL MOTION

If no external force acts on a system, what happens to the centre of mass?

• It accelerates randomly
• It moves in a circular path
• It moves with constant velocity or remains at rest
• It comes to rest immediately

What happens to the contribution of internal forces in the motion of the centre of mass?

• They dominate the motion
• They cause rotational motion only
• They cancel out due to Newton’s third law
• They increase the kinetic energy

How is the acceleration of the centre of mass related to external forces?

• M = A F_int
• M = A F_total
• M = A F_ext
• F = dp/dt

What does the centre of mass of a system of particles represent in terms of motion?

• The geometric centre of the body
• The heaviest point in the system
• The point where the entire mass of the system can be assumed to be concentrated for translational motion
• The point with zero velocity

Which equation represents the total momentum of a system of particles?

• M = + + + A a a a 1 1 2 2 ... n n m m m
• M = + + + V v v v 1 1 2 2 ... n n m m m
• F = ma
• τ = Iα