A fluid flowing out of a small hole in a vessel results in a backward thrust on the vessel.

Question

Explain why

A fluid flowing out of a small hole in a vessel results in a backward thrust on the vessel.

Answer 1

When a fluid flows out of a small hole in a vessel, it acquires a large velocity and hence has a large momentum. Since no external force is acting on the system, a backward velocity must be acquired by the vessel (By-law of conservation of momentum). As a result backward thrust is experienced by the vessel.