Question

what is kinetic energy?

Answer 1

 It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.

Answer 2

Hey!
Here is your answer!

Kinetic energy - The energy obtained by a body due to it's motion is called kinetic energy.
OR
When a body rolls or slides over another body, opposing force comes into play, that opposing force is called kinetic energy.