Shot types...

[Kobe 0]

Very good explanation. The numbers are a bit off because uniform decelleration would not mean Sakic's shot dropping 10mph while Blake's shot dropping 3mph from the same distance away from the net. Again, spin and resistance of course plays a huge part in this but holding them constant (so basically taking out decelleration due to resistance) would make the "quicker" shot the "harder" shot and vise-versa. If the goalie was brought to within a foot away from each player, then Sakic's shot would be the "harder" shot (assuming a nice uniform decelleration). It's the impact velocity that determines force on the goalie so Blake's shot would be the harder shot in the original example because his impact velocity is 72mph while Sakic's is 70mph.

This is kind of fun talking about this stuff. It reminds me of my high school and university days. The most science that I get these days is how far my fart will travel before someone notices.

[MDE3 0]

Very good explanation.  The numbers are a bit off because uniform decelleration would not mean Sakic's shot dropping 10mph while Blake's shot dropping 3mph from the same distance away from the net.  Again, spin and resistance of course plays a huge part in this but holding them constant (so basically taking out decelleration due to resistance) would make the "quicker" shot the "harder" shot and vise-versa.  If the goalie was brought to within a foot away from each player, then Sakic's shot would be the "harder" shot (assuming a nice uniform decelleration).  It's the impact velocity that determines force on the goalie so Blake's shot would be the harder shot in the original example because his impact velocity is 72mph while Sakic's is 70mph.

This is kind of fun talking about this stuff.  It reminds me of my high school and university days.  The most science that I get these days is how far my fart will travel before someone notices.

I showed Sakic's theoretical "non spinning shot" losing 12.5% velocity over whatever distance, and Blakes spinning shot losing 4% over the same distance, but assumed both shots decellerated at a "constant" though not "equal" rate. If the rate of decelleration was not "constant"..my assumptions of average speed would be incorrect.

The effect of aerodynamics on a puck could best be understood, if you thought of shooting a "flutter puck" versus a "flat" shot..this would illustrate an extreme of velocity differential due to air resistance. Because spin helps "laminar flow" of air over the surface of the leading edge of the puck..reducing resistance, it allows the puck to decellerate less rapidly and maintain it's flight profile in the air with greater stability. A puck with no spin will effectively see more "drag", lose it's flight profile and decellerate much more rapidly. I chose those numbers as an example for explanitory purposes, and do not mean to represent that these are in fact precise calculations..but are simply to show how spin could allow for the difference seen between a "heavy shot, and a "fast" shot.

To visualize this..think of the distance travelled of a thrown football with spin or without. The inertia of the spin not only helps the air flow, but the gyrascopic effect of the spin helps maintain the optimum "profile" of the ball through the air. The same thing is true of a puck....the more spin, the cleaner it will pass through the air and the longer it will retain it's trajectory(and speed).

[Kobe 0]

Dude, i'm agreeing with you about all the resistance and spin stuff so you don't have to keep trying to explain. You're giving the two shots different attributes of spin. The one that doesn't spin will of course decellerate much more quickly than the one that does. Imagine if both shots had the same spin, trajectory, air resistance... everything else other than velocity. The shot leaving the stick at the higher velocity (and having the higher impact velocity because spin, trajectory, etc. are the same for both shots) will produce the most force upon the goalie. With 2 identical shots regarding all other variables, the "quicker" shot will be the "harder" shot and vise-versa.

[Fedorov91 0]

You know, if I was still in school I'd do a Science Project on this and just copy and paste this thread for my report...

[JGraz15 53]

NERD ALERT!....and I am an auditor, that's bad

[MDE3 0]

uniform decelleration would not mean Sakic's shot dropping 10mph while Blake's shot dropping 3mph from the same distance away from the net.

sorry ..just explaining why I had to assume the rates of deceleration were "constant" for each of those two shots, but not "equal" in the example I gave. The math would not work for the average speed of each shot, if that was not true.

[asdfa 0]

LOL, I had a little run down with my science teacher about this one, as asdfa knows well.  I asked her if something could be harder but not faster, and she made me look stupid by using some velocity formulas.  On top of everything, she insulted me .  To the point:  Kobe is right.  I think chadd's comment about the spin on the puck is probably correct.

Well if she just used the F=MV formula to diss you then she should be bitch-slapped for being a science teacher because more force would be generated by something that's heavier vs. something lighter travelling at the same velocity (holding things like resistance constant of course).

actually, she accounted for all of the variables, stating that in when shooting a hockey puck, there is only one real variable, being velocity, since pucks all weigh the same.. or do they

anyway, after hockeyplayer11 tried to defend himself by saying something random about an unmeasurable force, she made a remark about hockeyplayer11's weight, and that's what really set him off

[MDE3 0]

actually, she accounted for all of the variables, stating that in when shooting a hockey puck, there is only one real variable, being velocity, since pucks all weigh the same.. or do they 

anyway, after hockeyplayer11 tried to defend himself by saying something random about an unmeasurable force, she made a remark about hockeyplayer11's weight, and that's what really set him off

Well that teacher is correct in the statement that only velocity governs the force where the mass is constant. However if she did not count the rotation of the puck her argument is incomplete. There can be two "velocities" involved: linear and rotational.

For her to negate spin would be scientifically innacurate.

Let's make it simple...

Two pucks are shot and reach the goalie at the same terminal velocity, except one puck is spinning and the other is not.

The puck which is not spinning has it's energy defined by: Mass times linear velocity squared (acceleration) only.

The puck which is spinning and travelling at the same linear speed when it hits the goalie has it's energy defined by: the Mass times linear velocity squared (acceleration) plus the mass times rotational velocity squared(acceleration)

There is more energy stored in the rotating puck than the non rotating puck.. and should certainly be what the goalie "feels" in the "heavier" shot.

I am not even mentioning losses due to the "drag" of a non rotating puck.

[Perry94 0]

ok...I'm gonna use this as my physics review!! I'm trying to rationalize this with simple physics...from the way I've seen players take shots, I'll conclude that with slappers, the puck starts at rest, while with a wrist shot, the puck is being pushed along before it is released (the sweeping motion). So...

I=Ft (t=amount of time of contact)

Blake (he's popular) takes a slapshot. He slaps the puck! Since the puck is at rest, there is no initial momentum, therefore P=0. Let's say that the stick contacts the puck for .1 seconds. If the puck flew at 80mph, then acceleration must have been very high, since it went from 0-80mph in .1 seconds. If the acceleration is high, then the Force must have been high (F=ma...the mass doesn't change).

Sakic (he's also popular) takes a wrist shot. He whips the puck, and it travels 80mph!! Since the puck was already moving, P>0. Chances are, he's had the puck on his blade for a bit before the shot was released, so let's say that the puck was on the blade for 1.5s. The acceleration from 0-80mph in 1.5s is not as much as the acceleration of the slapshot. The force must have been lower as a result.

Both shots have the same Impulse, however. The only difference is that with one shot, the force is higher, while the other shot, the time of contact is longer.

DOn't beat me down if I'm wrong...

[MDE3 0]

ok...I'm gonna use this as my physics review!! I'm trying to rationalize this with simple physics...from the way I've seen players take shots, I'll conclude that with slappers, the puck starts at rest, while with a wrist shot, the puck is being pushed along before it is released (the sweeping motion).  So...

I=Ft (t=amount of time of contact)

Blake (he's popular) takes a slapshot.  He slaps the puck!  Since the puck is at rest, there is no initial momentum, therefore P=0.  Let's say that the stick contacts the puck for .1 seconds.  If the puck flew at 80mph, then acceleration must have been very high, since it went from 0-80mph in .1 seconds.  If the acceleration is high, then the  Force must have been high (F=ma...the mass doesn't change).

Sakic (he's also popular) takes a wrist shot.  He whips the puck, and it travels 80mph!!  Since the puck was already moving, P>0.  Chances are, he's had the puck on his blade for a bit before the shot was released, so let's say that the puck was on the blade for 1.5s.  The acceleration from 0-80mph in 1.5s is not as much as the acceleration of the slapshot.  The force must have been lower as a result.

Both shots have the same Impulse, however.  The only difference is that with one shot, the force is higher, while the other shot, the time of contact is longer.

DOn't beat me down if I'm wrong...

You are exactly right as regards linear velocity. Also the slower release of Sakic's shot may impart more spin as it travels across the face of the blade..adding even more energy.

[SB39 2]

eiop: It's not a massive acceleration that gets the puck off the stick, its called jerk, which is the integral of acceleration with respect to time, which is the integral of velocity with respect to time, which is the integral of distance... And not to be mean, cuz I'm just an ex-physics major, it's not velocity squared, it's velocity divided by time again that makes acceleration. And I'm forgetting my rotational mechanics, with lamda and omega and all that jazz. Whatever, I'm a law major now, so I'll sue you if you shoot harder than me...