Wednesday, November 6, 2013

How Much Force Would You Feel When Being Hit by a Slap Shot?

As we're getting further into hockey season and there have already been some amazing shots, I wanted to look at the physics behind one of the most impressive shots in the sport to pull off, the slap shot. I wanted to find out how much force was exerted by the puck on a goalie and how much work was done by the puck during a slap shot.

Assumptions:

  • the puck was at rest before it was hit
  • the puck was about 40 ft away from the goalie
  • the puck accelerated at a constant rate


What we know:

  • mpuck = 6 ounces = 0.17 kg
  • vo = 0 m/s
  • vf = 108.8 mph (fastest slap shot ever recorded in NHL) = 48.6 m/s
  • t = 0.5 s
  • d = 40ft = 12.192 m
Calculations:

  • a = (vf - vo) / t = (48.6 - 0) / 0.5 = 97.25 m/s^2
  • F = ma = .17(97.25) = 16.53 N
  • W = Fd = 16.53(12.192) = 201 J
For an object with such a small mass, a hockey puck can sure impact a goalie with a decently-sized force when it is propelled forward by a slap shot. It also does quite a bit of work.

Resources:
http://sportsillustrated.cnn.com/nhl/news/20130308/top-10-nhl-slap-shots-of-all-time/

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