Question

A block of metal weighing 2 kg resting on frictionless plane. It is struck by a jet releasing water at a rate of 2 kg s at a speed of 5 ms 1. Calculate the acceleration of the block.​

Answer 1

Explanation:

ANSWER

Given that,

Mass m=2 kg

The speed of water v=5 m/s

The final velocity of mass of water after hitting the metal block is zero.

So, the average change in momentum per sec = initial momentum

=m×v

dt

dp

=1×5

dt

dp

=5 kgm/s

A this change in momentum occurs during 1 sec.

We may say that the force exerted on the 2 kg metal block is

F=

time

change in momentum

F=

1

5

=5 N

So, By Newton's law initial acceleration of the block is

F=ma

a=

m

F

a=

2

5

m/s

2

Hence, D is correct ,

Answered By priyanshi pareek