Question

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 at 5 ms–1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.

Answer 1

Answer:

Given:-

Mass of ball, m = 200 g = 0.2 kg      

Initial speed of ball, u = 10 m/s      

Final speed of ball, v = – 5 m/s

To Find:-

Change in momentum

Solution:-

Initial momentum = Mass × Initial speed

⇒ $0.2 \: kg \: X \: 10 m/s$            

⇒ $2 \: kg\: m/s$

Final momentum = Mass × Final Speed

⇒ $0.2 \: kg \: X (-5 \: m/s)$

⇒ $-1 \: kg \: m/s$

Then,

Change of Momentum = Final momentum - Initial momentum

⇒ 2 – (–1)

⇒ 2 + 1

= - 3 kg m/s

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

Here, Minus sign means the balls starting moving in opposite direction.

Explanation:-

Momentum  is the product of the mass and the velocity of an object or particle. It is a vector quantity. It is the property that a moving object has due to its mass and its motion.

Answer 2

Explanation:

Mass of the hockey ball, m= 200 g = 0.2 kg

Hockey ball travels with velocity, v1= 10 m/s  

Initial momentum = mv1  

Hockey ball travels in the opposite direction with velocity, v2= -5 m/s  

Final momentum = mv2  

Change in momentum = mv1- mv2= 0.2 [10 - (-5)] = 0.2 (15) = 3 kg m s-1  

Hence, the change in momentum of the hockey ball is 3 kg m s-1ty