Question

In order to swim a person pushes the water backward.why?

Answer 1

When we swim, we apply force and push the water backward with the help of our hands. In response to this action, the water pushes us forward with an equal force. Thus, in order to move forward and swim, the swimmer pushes the water backward.

Or.....

A swimmer push the water backwards to move forward because according to newton's 3rd law of motion in each and every action there is an equal and opposite force so if he push water backwards then acc. to newton's 3rd law he will move forward.

Answer 2

Every action has an equal and opposite reaction. Thus to move forward, we need to push backwards