Chapter 3.1, Problem 2cT

A block on a frictionless table is connected to a spring as shown. The spring is initially unstretched. The block is displaced to the right of point R and is then released.

1. When the block passes point R, is the spring compressed or stretched?

Does your answer depend on the direction in which the block is moving? Explain.

2. In the space provided, draw a free-body diagram for the block at the instant the block passes point R moving to the left. Draw arrows to represent the directions of the velocity, the acceleration, and the net force on the block, all at that instant. If any quantity is zero, state so explicitly.

Is the net work done on the block from point of release to point R, positive, negative, or zero? Explain.

At some instant, the block passes point L moving to the left. Draw a free-body diagram for the block at that instant. Also, draw arrows to represent the direction of the velocity, the net force, and the acceleration, all at that instant. If any quantity is zero, state so explicitly.

During a small displacement of the block from the right of point L to take the left of point L:

Is the net work done on the block positive, negative, or zero? Explain.

Does the speed of the block increase, decrease, or remain the same? Explain how your answer is consistent with the work-energy theorem.