Question

Which among the following options have mechanical energy in the form of potential energy only?

• A. Bird flying in sky.
• B. Train moving on an inclined plane.
• C. Book kept on the top of a shelf.
• D. Bird sitting on a tree.

Answer 1

Answer: (C), (D)

The correct options are
C Book kept on the top of a shelf.
D Bird sitting on a tree.

Mechanical energy is the sum of potential energy and kinetic energy.
Among the given options, book kept at the top of a shelf and bird sitting on a tree are at some height with respect to ground. Hence they possess only potential energy as they are not in motion whereas, flying bird and train moving on an inclined plane have both kinetic energy and potential energy.