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5/32 MCQs for:

Linear Momentum

A 50-kg pitching machine (excluding the baseball) is placed on a frozen pond. The machine fires a 0.40-kg baseball with a speed of 35 m/s in the horizontal direction. What is the recoil speed of the pitching machine? (Assume negligible friction.)

0.70 m/s.

0.14 m/s.

0.28 m/s.

4.4 x 103 m/s.

Consider two unequal masses, M and m. Which of the following statements is false?

If a uniform rod of mass m were to join the two masses, this would not alter the position of the center of mass of the system without the rod present.

The center of mass is closer to the larger mass.

The center of mass lies on the line joining the centers of each mass.

It is possible for the center of mass to lie within one of the objects.

A 0.060-kg tennis ball, initially moving at a speed of 12 m/s, is struck by a racket causing it to rebound in the opposite direction at a speed of 18 m/s. What is the change in momentum of the ball?

1.8 kgm/s.

0.72 kgm/s.

0.36 kgm/s.

1.1 kgm/s.

Two objects collide and stick together. Kinetic energy:

Is conserved only if the environment is frictionless.

Is definitely not conserved.

Is conserved only if the collision is elastic.

Is definitely conserved.

Two objects collide and bounce off each other. Linear momentum:

Is definitely conserved.

Is conserved only if the environment is frictionless.

Is definitely not conserved.

Is conserved only if the collision is elastic.