Mechanics #2 Free Response Question Solutions - AP Physics C 1998 Released Exam

The video tutorial covers a mechanics problem from the AP Physics C 1998 exam, focusing on collisions and energy conservation. It explains the setup of two scenarios involving a rod and clay system, calculates kinetic energy changes, and explores angular momentum conservation. The tutorial provides detailed step-by-step solutions, emphasizing the principles of momentum and energy conservation.

What is the initial condition of the rod system before the clay is sent towards it?

• The rod system is moving at a constant speed.

• The rod system is rotating.

• The rod system is initially at rest.

• The rod system is accelerating.

Why does the system only have translational kinetic energy after the collision?

• Because the collision is perfectly elastic.

• Because the system is in a gravitational field.

• Because the collision causes the system to rotate.

• Because the collision does not cause rotation.

How is the final velocity of the system determined after the collision?

• By using the conservation of energy.

• By measuring the distance traveled.

• By using the conservation of momentum.

• By calculating the force applied.

What is the change in kinetic energy as a result of the collision?

• It doubles.

• It increases by MV not squared over three.

• It decreases by MV not squared over three.

• It remains the same.

In the re-experimentation, where is the clay mass directed?

• Away from the rod system.

• Directly at the small dense object on the right.

• Towards the center of mass of the rod.

• Towards the left end of the rod.

What is the distance from the left end of the rod to the center of mass after the collision?

• 3L / 4

• L / 2

• 2L / 3

• L / 3

What is the direction of the motion of the center of mass immediately after the collision?

• Downward

• Upward

• To the left

• To the right

How is the angular speed of the system determined after the collision?

• By using the conservation of linear momentum.

• By using the conservation of angular momentum.

• By calculating the gravitational pull.

• By measuring the rotational force.

What is the final angular velocity of the system?

• V not over 4L

• V not over 3L

• V not over 2L

• V not over L

What is the change in kinetic energy in Part B compared to Part A?

• It is the same as in Part A.

• It is greater due to additional rotational kinetic energy.

• It is zero.

• It is less due to energy loss.