Question

A hockey player strikes a puck that is initially at rest. The force exerted by the stick on the puck is 975 N, and the stick is in contact with the puck for 0.0049 s.
(a) What is the impulse imparted by the stick to the puck.
___________ kg m/s
(b) What is the speed of the puck (m= 1.67 kg)just after it leaves the hockey stick?
____________ m/s

Answer 1

Explanation:

Given that,

The force exerted by the stick on the puck is 975 N

The stick is in contact with the puck for 0.0049 s

Initial speed of the puck, u = 0 (at rest)

(a) We need to find the impulse imparted by the stick to the puck.

Impulse = Force × time

J = 4.7775 kg-m/s

(b) Mass of the puck, m = 1.76 kg

We need to find the speed of the puck just after it leaves the hockey stick.

Let the speed be v.

As impulse is equal to the change in momentum.

$J=m(v-u)\\\\4.7775=1.67(v-0)\\\\v=\dfrac{4.7775}{1.67}\\\\v=2.86\ m/s$

So, when the puck leaves the hockey stick its speed is 2.86 m/s.