Question

Explain why fireman directs a powerful stream of water on a fire from a hose pipe tend to go backward

Answer 1

According to the circumstances mentioned in the question that,

a powerful stream of water on a fire from a hose pipe tend to go backward.

This phenomenon is the practical life example of the Newton's third law,"every action has a same and opposite amount of reaction."

The water stream applies a force on the opposite side of the fireman, that's why a repellent opposite force is also applied on the fireman, himself.

That's why he tend to move backwards automatically.

Answer 2

Explanation:

According to Newton's 3rd law of motion, every action has equal and opposite reaction.

Thus stream of water going in forward direction exerts a force on the fire man in the backward direction which makes him to go backwards.