Injuries

[billybud]

Mass X speed = momentum

The kids are heavier and faster today....and when they are coming at each other in a collision...the forces involved are more than tendons, muscles, and bones can sometimes bear.

Receivers aren't able to catch the ball uncontested as much...speedy and muscular defensive backs are hitting them with the force of a full run behind them.

When some of today's quarterbacks are weighing what NFL linemen were weighing back in 1970, it shows a progression of size.

FSU plays a jumbo package...in that package the fullback is 306, the RB is 237, the tight end is 280....

[Old Ducker]

The forces involved have changed as well....

NFL Defensive Tackles averaged in at 256 pounds in 1970...306 pounds by 2006 and still moving up.

Offensive Tackles averaged 259 lbs in 1970 versus 317 by 2006...

Absolutely....when Coriolis was teaching Mr. Billbud physics, he remembered well. Force over distance.

Well I should have figured that Dr. Donovan would come up with a witty and erudite comment that comes out of nowhere. I wish I could do that.

[Duke1632]

Mass X speed = momentum

But wouldn't xfer of kinetic energy be more appropriate than momentum? Particularly in the case of pain/injury. In that case, the important equation is: E = 1/2 mv^2. Given mass is still linear (as with momentum), the real killer is velocity/speed, since you square that factor. So:

300lbs at 10mph vs.
150lbs at 20mph.

Both have the same momentum, but the little guy moving twice as fast transfers twice as much energy = hurts more. Not sure, but that seems right to me.

[donovan]

You're up, Mr. Billybud........

[Duke1632]

After a bit more thought, I'm sure the above is right. It's easier to see with the below demonstration:

1lb baseball traveling at 100mph vs.
100lb uranium rock at 1 mph.

-Momentum (p = mv)
baseball: 1 X 100 = 100
rock: 100 X 1 = 100

So both have the same momentum. Now for energy xfer:

-Energy (E = 1/2 mv^2)
baseball: 0.5 X 10,000 = 5000
rock: 50 X 1 = 50

So the baseball xfers 100 times more energy than the rock, even though they have the same momentum. I expect many of you can tell me from experience which hurts more between a fast/light baseball and a heavy/slow rock.

The moral is increased speed leads to much more devastating collisions than increased mass. In a way, this might be an answer to the initial injuries questions--about injuries being more severe than in the past. I expect players are a lot faster these days.

[donovan]

A heavy rock hurts more...because when you are hit with a baseball you have thousands of fans booing the pitcher and applauding you as you take first base....Rock you are just told to suck it up.

Early hitter..Ruth Cobb etc believe that heavier bats made the ball go a farther....and they had some on the field argument that was pretty sound...but we believe today bat swing is more important.....hence cork bats and titanium bats with a coefficient of "zero"...black marketed on to college ranks..I digress, are better.

[Duke1632]

Early hitter..Ruth Cobb etc believe that heavier bats made the ball go a farther....and they had some on the field argument that was pretty sound...but we believe today bat swing is more important.....hence cork bats and titanium bats with a coefficient of "zero"...black marketed on to college ranks..I digress, are better.

In a collision between a bat and a ball, momentum might be more appropriate. Here, you are concerned with how far the ball will travel after the collision (which relates more to momentum), not how much damage the ball takes from the collision (which relates more to energy xfer). If that's the case, then heavy vs. light bats do not matter much, but rather, optimizing the weight vs. speed of swing for a particular batter. Probably, though other principals of physics are more important here, like maximizing the length of contact between the bat and the ball and elastic vs. inelastic contact, where the batter would want a bat (and ball) that is most inelastic.

[Old Ducker]

A heavy rock hurts more...because when you are hit with a baseball you have thousands of fans booing the pitcher and applauding you as you take first base....Rock you are just told to suck it up.

Early hitter..Ruth Cobb etc believe that heavier bats made the ball go a farther....and they had some on the field argument that was pretty sound...but we believe today bat swing is more important.....hence cork bats and titanium bats with a coefficient of "zero"...black marketed on to college ranks..I digress, are better.

I suspect the heavy bat advocates are right. Drop a baseball off a five story building onto a thick sheet of plywood, supported by a couple of blocks, or to concrete on the ground (the heaviest bat imaginable) and see from which it bounces highest. I think the latter; the lighter bat will absorb more of the energy and transfer it to the batter. If this is right then the tradeoff becomes the weight of the bat vs. the strength of the man to swing it with sufficient force to overcome its' inertia. With some decent data this could be plotted on a graph.

[billybud]

Drop a piece of paper of of a 35 story building and a cannonball...and see which makes a dent.

[Derek]

But how does that relate to this hit???? Ouch.

http://www.saturdaydownsouth.com/2013/targeting-rule-sec-review/


And HOW is this hit a penalty?

[Duke1632]

Drop a baseball off a five story building onto a thick sheet of plywood, supported by a couple of blocks, or to concrete on the ground (the heaviest bat imaginable) and see from which it bounces highest. I think the latter; the lighter bat will absorb more of the energy and transfer it to the batter.

But in this scenario, neither the plywood nor the concrete have any effective momentum. Both are stationary, so can only apply a normal force to the ball. The ball will bounce higher from the concrete, but not due to the weight or momentum of the concrete, rather due to the rigidity of the concrete affecting a more inelastic collision.

If this is right then the tradeoff becomes the weight of the bat vs. the strength of the man to swing it with sufficient force to overcome its' inertia. With some decent data this could be plotted on a graph.

In a fake math world, where all collisions are perfectly inelastic, the momentum of the bat is the only factor in determining how far the ball will go after the collision. And as billybud told us momentum = mass X speed. Therefore, increasing either the mass or the speed of the bat will have equally proportional increases in effect. Therefore, a really strong man who can swing a heavy bat just as fast as he can swing a lighter bat, will certainly perform better with the heavy bat. However, a weaker/faster man who can swing a lighter bat much faster than a heavy bat might actually have better performance with a light bat (assuming the increased speed of the swing can overcome the decreased mass of the bat). In fact, the faster, less strong man might actually hit the ball farther if his swing speed is fast enough with the lighter bat. Again, it all comes down to mass (of bat) X velocity (of bat), and optimizing that equation would appear to be something unique to each batter. In the real world, where collisions are never actually perfectly inelastic, other considerations arise such as the composition (apart from weight) of the bat. I'm not sure if this is interesting to anyone, but there it is.

[donovan]

I think I will concentrate on the immensity of space...something I have a modicum of chance of understanding......

HOWEVER....Bats use to weigh up to 48 oz....now they top out at about 34 oz. Why, you ask....so they can swing faster. If you could swing a 48 oz bat with the same velocity as a 34 ounce bat...then the ball would go farther, or is the further....it's farther, so don't bother.....I digress......BUT you can't so we opt for speed over weight...the solution....steroids....it is always so simple.

[Spence]

I think I will concentrate on the immensity of space...something I have a modicum of chance of understanding......

HOWEVER....Bats use to way up to 48 oz....now they top out at about 34 oz. Why, you ask....so they can swing faster. If you could swing a 48 oz bat with the same velocity as a 34 ounce bat...then the ball would go farther, or is the further....it's farther, so don't bother.....I digress......BUT you can't so we opt for speed over weight...the solution....steroids....it is always so simple.

That is right. If you could get a 60 oz. bat around with the same bat speed at you could a 34oz. bat it would travel further. Getting a 60oz. bat around, though, can be a real drag.

[Cane from the Bend]

Getting a 60oz. bat around, though, can be a real drag.

I thought that was how Mrs. Spence got you to the alter

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[Cane from the Bend]

Drop a baseball off a five story building onto a thick sheet of plywood, supported by a couple of blocks, or to concrete on the ground (the heaviest bat imaginable) and see from which it bounces highest. I think the latter; the lighter bat will absorb more of the energy and transfer it to the batter.

But in this scenario, neither the plywood nor the concrete have any effective momentum. Both are stationary, so can only apply a normal force to the ball. The ball will bounce higher from the concrete, but not due to the weight or momentum of the concrete, rather due to the rigidity of the concrete affecting a more inelastic collision.

If this is right then the tradeoff becomes the weight of the bat vs. the strength of the man to swing it with sufficient force to overcome its' inertia. With some decent data this could be plotted on a graph.

In a fake math world, where all collisions are perfectly inelastic, the momentum of the bat is the only factor in determining how far the ball will go after the collision. And as billybud told us momentum = mass X speed. Therefore, increasing either the mass or the speed of the bat will have equally proportional increases in effect. Therefore, a really strong man who can swing a heavy bat just as fast as he can swing a lighter bat, will certainly perform better with the heavy bat. However, a weaker/faster man who can swing a lighter bat much faster than a heavy bat might actually have better performance with a light bat (assuming the increased speed of the swing can overcome the decreased mass of the bat). In fact, the faster, less strong man might actually hit the ball farther if his swing speed is fast enough with the lighter bat. Again, it all comes down to mass (of bat) X velocity (of bat), and optimizing that equation would appear to be something unique to each batter. In the real world, where collisions are never actually perfectly inelastic, other considerations arise such as the composition (apart from weight) of the bat. I'm not sure if this is interesting to anyone, but there it is.

I think I will concentrate on the immensity of space...something I have a modicum of chance of understanding......

Good, then let's use space as a metaphor . . .

The Motion of the Earth in travel vs the velocity of Meteor/Asteroid.
No deflection or bounce; you wind up with a crater. (broken bat?)

Now, would a comet bounce (skip), not likely --- then again, comets seem only to get caught in out gravity, spin in orbit for a few days, then fire back off into space ... or maybe that is the astronomical equivalence of Earth's outer atmosphere (exosphere) being the bat, sending the comet (baseball) in a deflective trajectory . . .

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