A hockey ball of mass 200 g travelling at 10 ms-1 is struck by a hockey stick so as to return it along its original path with a velocity of 5 ms-1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.


Firstly, we will calculate the initial momentum:

Given,

Mass of hockey ball, m1 = 200 g
(We know that 1kg=1000gram)

= kg

= 0.2 kg

Initial velocity, v1 = 10 m/s (Given)


So,


Initial momentum = m1 × v1
= 0.2 × 10

= 2 kg m/s (i)


Now, we will calculate the final momentum:


Given,


Mass of hockey ball, m2 = 200 g
(We know that 1kg=1000gram)

= 0.2 kg

Final velocity, v2= - 5 m/s (As the ball is going in reverse direction)

So,

Final momentum = m2 × v2

= 0.2 × (-5)

= - 1 kg m/s (ii)


Now,

Change in momentum = Final momentum – Initial momentum

= -1 -2

= (- 3) kg m/s

Therefore, the change in momentum of the hockey ball is 3 kg m/s.

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