Question

a block of metal weighing 2 kg is resting on a frictionless plane. it is strunk by a jet releasing Water at rate of 1 kg/s and at speed of 5 m/s the initial acceleration of block will ​

Answer 1

ANSWER

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

So the average change in momentum per sec = initial momentum

=mass×initial velocity of water

=1kg×5m/s=5kgm/s

As this change in momentum occurs during 1 sec. We may say that the force exerted on the 2kg metal block is

F=change in momentumtime

=5kgm/s1s=5N

Hence by Newton's law initial acceleration of the block of mass m=2kg is given by

a=Fm=5N2kg=2.5m/s2

Answer 2

F = v dm/dt

= 5 x 1

= 5N

acceleration= a = F/m

= 5/2

= 2.5 ms⁻²