A 0.105-kg hockey puck moving at 24 m/s is caught and held by a 75-kg goalie at rest. With what speed does the goalie slide on the ice after catching the puck?

Question

24888 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-02-14T20:17:43

The goalie slides with a speed of 0.034 m/s after catching the puck. Use conservation of momentum to solve this question.

The momentum of the puck before it is caught:

#p_(puck) = 24 \ m s^-1 times 0.105 \ kg = 2.52\ kg \ m s^-1.#

After catching the puck, all the momentum is transferred to the goalie. Using conservation of momentum:

#Speed \ of \ goalie = (2.52\ kg \ m s^-1)/(75kg + 0.105kg).#

Notice that as the goalie caught the puck, their combined mass is used for the final momentum calculation.

#Speed \ of \ goalie = (2.52\ kg \ m s^-1)/(75.105 \ kg).#

#Speed \ of \ goalie ~= 0.034 \ m s^-1.#

The goalie slides with a speed of 0.034 m/s after catching the puck.