A 5-kg fish swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish at rest.The speed of the larger fish after this lunch is

Question

Quizplus · Accepted Answer

The total momentum before the two fish collide is:

(5 kg) x (1 m/s) + (1 kg) x (0 m/s) = 5 kg m/s

The total momentum after the two fish collide is:

(5 kg + 1 kg) x v
where v is the speed of the larger fish after lunch.

Using conservation of momentum:

(5 kg + 1 kg) x v = 5 kg m/s

Simplifying:

6 kg x v = 5 kg m/s

v = 5/6 m/s.

Therefore, the correct choice is C.

A 5-Kg Fish Swimming at a Speed of 1 M/s