Question

Suppose an object's initial velocity is 10 m/s and its final velocity is 4 m/s. Mass is constant.

What can best be concluded about the object based on the work-energy theorem?
A. Work is positive, the environment did work on the object, and the energy of the system increases.
B. Work is positive, the object did work on the environment, and the energy of the system increases.
C. Work is negative, the object did work on the environment, and the energy of the system decreases.
D. Work is negative, the environment did work on the object, and the energy of the system decreases.

Answer 1

The object's final kinetic energy is less than its initial kinetic energy due to a decrease in velocity from 10 m/s to 4 m/s, which means that the object did negative work on the environment resulting in a decrease in the system's energy.

Step-by-step explanation:

Based on the work-energy theorem, if an object slows down there is a negative change in its kinetic energy, indicating that the net work done on the object is also negative. The correct conclusion about the object when it changes from an initial velocity of 10 m/s to a final velocity of 4 m/s, while the mass remains constant, is that the object has done work on the environment. The work is considered negative because the object's energy decreases due to a reduction in velocity. Therefore, the work has been done by the object on the environment, not the other way around, leading to a decrease in the system's energy.