Question

If there is a nonzero net force acting on an object for some time, which of the following must be true?
I. The object is gaining kinetic energy
II. The object experiences displacement
III. There is work being done on the object

• A. I only
• B. I and II only
• C. I and III only
• D. II and III only
• E. I, II, and III

Answer 1

Answer: (D)

II and III only

If $F_{net}$ acting on the object is non-zero, the acceleration of the object is non-zero.

Hence the speed of objects is either increasing or decreasing.

Hence the kinetic energy may be gaining or losing kinetic energy. Hence statement I is not correct.

However since the speed is non-zero, the object continuously experiences displacement.

Also the work done on object is $\overrightarrow{F}.\overrightarrow{s}$ which is non-zero.
Hence correct answer is option D.