Question

When an arrow is shot from its bow, it has $K.E.$ from where does it get $K.E.$ ?

Answer 1

We should apply the law of conservation of energy. Law of conservation of energy states that energy can neither be created nor be destroyed but can only be transformed from one form to another. Energy conversion is the main source of providing energy for any particular work.

Complete answer:
We know that it is impossible to create energy by any process and in this case also kinetic energy cannot be created but can only get converted from the potential energy of the bow when it is stretched. This whole process is based on the principle of conservation of energy which states that energy can neither be created nor be destroyed but can only be transformed from one form to another.
Hence, when an arrow is shot from its bow then the potential energy is converted into kinetic energy based on the principle of conservation of energy.

Additional Information:
We should know the basics of kinetic energy and potential energy respectively for better grip on the mentioned topic.
$(i)$ Kinetic Energy- Energy of a body due to its motion or velocity is called kinetic energy of that body. Kinetic energy of a stationary body is always zero.
$(ii)$ Potential Energy- Energy of a body due to its shape and position is called its potential energy. Potential energy of a moving body is always zero.
The sum of kinetic energy and potential energy is called mechanical energy of a system.
We should also know the law of conservation of mechanical energy. This law states that for an isolated system the mechanical energy always remains conserved.

Note:
We should keep in mind that the source of any form of energy is always another form of energy by energy conversion process. For a mechanical system the sum of potential energy and kinetic energy always remains the same. Kinetic energy of a body at rest is always zero and potential energy of a moving body is always zero.