Question

A hockey ball of mass 200 g travelling at 10 m/s is struck by a hockey stick so as to return it along it's original path with velocity of 5 m/s. Calculate the change of momentum occured in motion of hockey ball of Force applied by hockey stick.


Answer is 3, Give explanation
I've to submit my hw plzz ​

Answer 1

Solution :

a) Calculation of initial momentum

• Mass of hockey ball, $\sf\: m_{1}$ = 200 g i.e 0.2 kg

• Initial Velocity $\sf v_{1}$ = 10 m/s

So,

★ Initial momentum = $\sf\: m_{1}\: \times v_{1}$

→ Initial momentum = 0.2 × 10

→ Initial momentum = 2 kg m/s

b) Calculation of Final Momentum

• Mass of hockey ball , $\sf\: m_{2}$ = 200 g i.e. 0.2 kg

• Initial Velocity $\sf\: v_{2}$ = -5 m/s (Reverse Direction)

★ Final momentum = $\sf\: m_{2}\: \times \: v_{2}$

→ Final momentum = 0.2 × ( -5)

→ Final momentum = -1 kg m/s

Now,

★ Change in momentum = Final Momentum - Initial Momentum

→ Change in momentum = -1 - 2

→ Change in momentum = -3 kg m/s

$\therefore$ Change in momentum of the hockey ball is 3 kg m/s.