Question

explain why it is difficult for a Fireman to hold a hose which ejects large amount of water at high velocity

Answer 1

According to Newton's Third law
Higher will be the velocity of water higher will be the force required to counter the force produced by it.

Answer 2

Answer:

When a fire hose pipe ejects large amount of water in the forward direction at a high velocity, then the forward going stream of water exerts a backward reaction force due to which the hose pipe tends to go backward and slips from the hands of fireman. This backward movement of hose pipe makes it difficult for a Fireman to hold a hose pipe. And the Fireman has to hold the hose pipe strongly.