Chapter 5, Problem 10RAT

A big fish swims upon and swallows a small fish at rest. After lunch, the momentum of the big fish is

(a) the same as before.

(b) less than before.

(c) more than before.

(d) zero.

To determine

The correct option for the statement, “A big fish swims upon and swallows a small fish at rest. After lunch, the momentum of the big fish is”.

Answer to Problem 10RAT

The correct option for the statement, “A big fish swims upon and swallows a small fish at rest. After lunch, the momentum of the big fish is” is option (a).

Explanation of Solution

The momentum for a system before and after the event always remains conserved until an external force is acted upon it. It means that when the first object collides with another object, then the momentum of the system will be the same before the collision and after the collision.

In the case, when big fish eats the small fish at rest, an inelastic collision occurs as both the fish move together. The speed of big fish gets reduced, but the mass of the fish gets increased by eating small fish. So, the momentum of big fish before and after eating the small fish will remain the same.

Conclusion:

Therefore, the correct option for the statement, “A big fish swims upon and swallows a small fish at rest. After lunch, the momentum of the big fish” is option (a).