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Show on a diagram how your CM shifts when you move from a lying position to a sitting position.

A 0.060-kg tennis ball, moving with a speed of 5.50 m/s has a head-on collision with a 0.090-kg ball initially moving in the same direction at a speed of 3.00 m/s. Assuming a perfectly elastic collision, determine the speed and direction of each ball after the collision?

If only an external force can change the momentum of the centre of mass of an object, how can the internal force of the engine accelerate a car?

Two billiard balls of equal mass undergo a perfectly elastic head-on collision. If one ball’s initial speed was 2.00 m/s and the other’s was 3.60 m/s in the opposite direction, what will be their speeds and directions after the collision?

A rocket following a parabolic path through the air suddenly explodes into many pieces. What can you say about the motion of this system of pieces?

A 0.280-kg croquet ball makes an elastic head-on collision with a second ball initially at rest. The second ball moves off with half the original speed of the first ball.

(a) What is the mass of the second ball?

(b) What fraction of the original kinetic energy \(\left( {\frac{{{\rm{\Delta KE}}}}{{{\rm{KE}}}}} \right)\) gets transferred to the second ball?

(I) A constant friction force of 25 N acts on a 65-kg skier for 15 s on level snow. What is the skier’s change in velocity?

A light object and a heavy object have the same kinetic energy. Which has the greater momentum? Explain.

A ball of mass m makes a head-on elastic collision with a second ball (at rest) and rebounds with a speed equal to 0.450 its original speed. What is the mass of the second ball?

A ball of mass 0.220 kg that is moving with a speed of 5.5 m/s collides head-on and elastically with another ball initially at rest. Immediately after the collision, the incoming ball bounces backward with a speed of 3.8 m/s. Calculate

(a) the velocity of the target ball after the collision, and

(b) the mass of the target ball.