A body moves with decreasing speed.Which of the following statements is true?
A)The net work done on the body is positive,and the kinetic energy is increasing.
B)The net work done on the body is positive,and the kinetic energy is decreasing.
C)The net work done on the body is zero,and the kinetic energy is decreasing.
D)The net work done on the body is negative,and the kinetic energy is increasing.
E)The net work done on the body is negative,and the kinetic energy is decreasing.

Question

Quizplus · Accepted Answer

When a body moves with decreasing speed, it means its kinetic energy is decreasing. According to the work-energy principle, the net work done on a body is equal to the change in its kinetic energy. Here, the kinetic energy is decreasing, therefore the net work done on the body must be negative. Hence, the correct option is (E) – The net work done on the body is negative, and the kinetic energy is decreasing.

A Body Moves with Decreasing Speed