Q. 254.0( 13 Votes )
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)
Initial momentum = m1 × v1
= 0.2 × 10
= 2 kg m/s (i)
Now, we will calculate the final momentum:
Mass of hockey ball, m2 = 200 g
(We know that 1kg=1000gram)
Final velocity, v2= - 5 m/s (As the ball is going in reverse direction)
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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