Friday, 2 March 2012

Whaddya Mean "Heavy Shot"?

There are many terms used in and around the game of hockey that wouldn't make very much sense if taken literally. After all, if a goaltender "threw a cheeseboard" at a player, you'd assume he was in a kitchen of some sort rather than punching a player with his blocker. While watching hockey last night, I heard the term "heavy shot" used. I didn't give it much thought then, but I will today thanks to meeting up with friend of HBIC (FOHBIC) Stu E. while on my lunch hour.

Stu made a good point when he said that physics don't allow for a heavier shot than anyone else because the mass of the puck is constant for each and every player. He's right, of course, but how did this term of "heavy shot" come about then? What makes a shot "heavier" than any other shot?

The physics equation that Stu is referring to is the equation for finding Force (F). The easiest way to find that is through mass (m) multiplied by acceleration (a), but if the mass is always constant, it can be represented as 1. Therefore, force = acceleration, or, if expressed as an equation,

F = m * a

F = 1 * a

F = a

Each player has a different amount of force they can place on the puck through due to a variety of factors, so force really does equal acceleration when it comes to firing a puck. But that doesn't factor in any sort of "heaviness" in terms of the shot, so I went looking for more information than just what Sir Isaac Newton could provide.

There was a great discussion in the comments over on SB Nation's Lighthouse Hockey about this very topic back in January. Commenter "afrosupreme" wrote,
"... I’ve always assumed it has to do with someone who can generate a lot of spin (in essence, torque) on the puck. That shot would have more momentum and require a greater opposing force to stop, thus feeling 'heavier.'

"I’m kind of guessing here, but that’s what I also assumed was the case when I was a catcher. Breaking pitches often felt heavier to catch than fastballs moving with greater velocity, which I chalked up to the increased spin."
That seems logical, actually. When you think about it, the goaltender is simply stopping the forward motion of the puck if fired directly at him with no spin. If the puck leaves the stick while spinning, the goaltender has to stop both the forward motion of the puck AND the spinning motion of the puck as it hits him. In short, it requires extra effort to stop a slapshot with a spinning puck than it does to stop a slapshot where the puck doesn't spin.

I continued searching for more explanations. Commenter "TartanBill" of The Goalie Store added his thoughts to the "heavy shot" phenomenon in April 2001 when he wrote,
"Both kinetic energy and momemtum have translational and rotational components. Consider that the leading edge of a rapidly rotating puck will be moving with considerably greater speed than just the puck's shot velocity. It requires a great deal of resistance applied in a very short time to stop that rotation."
I'm no physicist, but that makes sense. You have to stop the puck and stop the spinning of the puck at the same time. It would require more opposite force to stop both motions than just the motion of a puck fired with no spin.

Physics tells us that a shot fired at 100mph will reach the net in 0.34 seconds from the blueline. Without getting into crazy equations and turning HBIC into Physics Blog In Canada, I can honestly say that I subscribe to the spinning puck theory that a heavy shot does have a significant amount of spin happening. I should know since I've definitely blocked a few shots in my time as a defenceman, and it's not always the guy with what appears to be a big shot who leaves the ugliest bruises.

Does Zdeno Chara have a heavy shot with his 109mph blast? Since he holds the fastest shot record, I'd say yes. But if he adds some spin onto the puck, there's no denying that his shot is literally like a bullet when it hits a goaltender.

Until next time, keep your sticks on the ice!

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