Question

Complete each statement about the sign of the work done on a baseball. Carlton catches a baseball and his hand moves backward as he brings the ball to a halt, doing work on the baseball. Carlton throws a baseball, doing work on the baseball. Carlton carries a baseball in his hand as he rides his bicycle in a straight line at constant speed, doing work on the baseball. Carlton carries a baseball in his hand as he rides his bicycle in a straight line with increasing speed, doing work on the baseball.

Answer 1

Answer and Explanation:

• The work done is negative as the force is applied in the forward direction and the displacement of the hand is in the backward direction.
• The work done is positive as the work is done on the baseball by Carlton. Moreover, both the force applied and the displacement of Carlton are in a straight line in the forward direction.
• The work done in this case is zero as Carlton rides with constant speed, the Kinetic energy too remains constant and hence net work done is zero.
• The work done in this case is positive as the work is done on the baseball by Carlton and as the velocity changes its Kinetic energy also varies wit it.
• Also the force applied and the displacement of Carlton in this case are in the directed to the same path.