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Shot Velocity Question

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Old
07-02-2010, 03:36 AM
  #26
Giroux tha Damaja
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Quote:
Originally Posted by donGjohnson View Post
I'm no physicist, but I always see higher speed when shooting lighter objects. I've also found that true when throwing things, generally. Obviously however, they cause less force of impact. I think it's no coincidence, though I can't recall the specific term for this, I'm pretty sure there is one...
One is velocity (speed), and the other is momentum (speed x mass). Makes perfect sense.

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07-02-2010, 08:00 AM
  #27
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Momentum (Mass x Velocity) is conserved.
(Stick x Velovity) = (Puck x Velocity).

Decrease Puck weight, increase Velocity. That is the answer to the perfect, closed system question.


That said, the biggest I see is the compression of the puck. Some of the velocity of the stick will go into compressing the puck and I don't know the difference in dynamics of the two pucks. Will the heavier puck compress more and thus provide more of a launch off the the stick? I don't know.

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07-02-2010, 08:05 AM
  #28
Crosbyfan
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Quote:
Originally Posted by I am The Mush View Post
I agree with you 100%.

Momentum is measured in Joules. Mass x Velocity gives momentum. If you release the same number of Joules of energy into two stationary pucks they both end up with the same momentum.

.
Momentum is not measured in Joules. Mass x Velocity does give momentum. Kinetic energy, 1/2 mass X velocity squared,(can be measured in Joules) and momentum are not the same thing.

If you release the same number of Joules of energy into two stationary pucks with different mass they both cannot end up with the same momentum.

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07-02-2010, 11:09 AM
  #29
Gino 14
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Quote:
Originally Posted by Orange Crush 89 View Post
All right, this might seem like a stupid question, but there's nothing wrong with asking. Heck, there may not even be a scientific answer, but anyway... Does the weight of a puck bear any effect on the velocity of a shot? For example; what would the difference be between the clocked speed of a floor hockey puck (roughly 0.9oz) vs a street or ice hockey puck (roughly 5.5/6.0oz)? Would it be faster, slower or no significant difference?
Since weight is not a factor in velocity (v = d x t), a clocked speed of 60 mph for a floor hockey puck is exactly the same as a clocked speed of 60 mph for an ice hockey puck.

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07-02-2010, 01:27 PM
  #30
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Quote:
Originally Posted by Crosbyfan View Post
Momentum is not measured in Joules. Mass x Velocity does give momentum. Kinetic energy, 1/2 mass X velocity squared,(can be measured in Joules) and momentum are not the same thing.
Whoops, (Kg-meters)/second is the measurement for momentum.

Quote:
Originally Posted by Crosbyfan View Post
If you release the same number of Joules of energy into two stationary pucks with different mass they both cannot end up with the same momentum.
D'oh, I have committed the classic beginner-physicist's mistake of interchanging momentum and kinetic energy (which obviously doesn't work since m*v^2 =/= mv, except for certain specific sets of numbers). I should have known better.

That said, if you subject two pucks to the same impulse, it still holds true that the heavier puck is going to have less velocity than the lighter puck. The extent to which this is true would be less than I was saying, due to the differences in the equations used, but it is still true in a qualitative sense which is all we're trying to get at here (not to say that I don't appreciate you highlighting the distinction and my mistake).

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Old
07-06-2010, 02:58 PM
  #31
Hounsy
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Would the puck hold it's velocity better due to more weight? As a goalie it feels like it does. Meaning the ball may have a higher peak but the puck may have a better average over the distance?

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Old
07-06-2010, 03:17 PM
  #32
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Goalies tend to "feel" pucks more when they spin faster. Same shot speed but certain players shoot heavier. Same thing with baseball, some guys pitches feel heavier, it's almost feels like hitting a small bowling ball. Those pitchers are generally known to break more bats.

Goalies, in pads, won't feel a roller hockey ball but they feel pucks depending on speed and "heaviness" of the shot.. I dont think I've ever heard of any goalie complain about an inline puck without it making it through the padding but I've definitely seen goalies go down from a shot on ice. I've taken down a friend of mine more than once... always feel bad too.

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Old
07-06-2010, 06:46 PM
  #33
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Jebus.

Straight, no BS answer: Yes, given the same shot, the light puck will go faster.

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Old
07-06-2010, 07:57 PM
  #34
Crosbyfan
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Quote:
Originally Posted by SEALBound View Post
Jebus.

Straight, no BS answer: Yes, given the same shot, the light puck will go faster.
Same shot is not the same...

Why didn't we think of that?

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Old
07-06-2010, 08:51 PM
  #35
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A lighter puck will leave your stick at a faster speed (you're applying the same force to less mass, so there will be more acceleration), but will also be slowed down more by air resistance after it leaves you stick. In general, at normal distances, I definitely think my shot is faster with the light street hockey pucks, but if you were to measure the speed on some ridiculous full rink slap shot, I could see the heavier puck being faster at the end due to being slowed down significantly less by air resistance.

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