Shooting a hockey puck

Hockey players use their sticks to shoot a puck of mass m = 165 g towards the goal.

San Jose Sharks Forward Jeff Friesen demonstrates a one-timer.

Can you figure out how hard the blade of the stick (which has a mass of about M = 185 g, about the same as that of the puck) whacks the puck? Consider these strategic snapshots: first, two before the impact:

time = 0 s	time = 0.43 s

And now, two pictures taken just after impact.

time = 0.43 s	time = 0.50 s

1. What is the initial velocity of the puck?
2. What is the final velocity of the puck?
3. What is the change in the puck's momentum?
4. Estimate the average force exerted by the stick on the puck during the collision.

For more information

• The Exploratorium's Science of Hockey website is a great source. I grabbed information and the photographs above from it.

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.