Batted Ball Distance

[Eric F]

From Dr. Russell, "a gain in batted-ball speed only results if you are swinging the same bat faster. Swinging a lower MOI bat faster does not resulting in a faster batted-ball speed. This is because the effectiveness of the collision between bat and ball depends on the MOI of the bat, and a lower MOI bat produces a less effective collision with the ball. If the bat-swing speed is held constant, a bat with a lower moment-of-inertia produces a less-effective collision with the ball such that the batted-ball speed actually decreases for the lower MOI bat. In fact, when a player switches to a lower MOI bat, the increase in batted-ball speed due to higher swing speed is almost exactly cancelled out by the reduction in batted-ball speed because the lower MOI bat impacts the ball less effectively."

Since the same bat is not being used it is possible the girl with the slower swing speed is using a bat with a higher moment of inertia

This wouldn't explain the opposite results off a tee.

 

[BadMonkeys]

This wouldn't explain the opposite results off a tee.

Here's what I am getting from the info, a higher MOI bat may produce a greater batted ball speed, resulting in a longer batted ball distance despite a slightly lower swing speed; the higher MOI produces a more effective collision. A lower MOI bat may be allowing the increased bat speed of girl #2 but decreasing her batted ball speed and batted ball distance.

I admit, I am not a physicist, I could be misunderstanding. Also we don't know the MOI of the bats being used.

 

[Stever]

Good point BadMonkeys, I am suspecting one bat IS hotter than the others, but not 100% sure

 

[Eric F]

Here's what I am getting from the info, a higher MOI bat may produce a greater batted ball speed, resulting in a longer batted ball distance despite a slightly lower swing speed; the higher MOI produces a more effective collision. A lower MOI bat may be allowing the increased bat speed of girl #2 but decreasing her batted ball speed and batted ball distance.

I admit, I am not a physicist, I could be misunderstanding. Also we don't know the MOI of the bats being used.

In that case, we would expect that the same girl who hit farther off a pitched ball would ALSO hit farther off a tee. This isn't what Stever observed.

 

[BadMonkeys]

In that case, we would expect that the same girl who hit farther off a pitched ball would ALSO hit farther off a tee. This isn't what Stever observed.

I got it now Eric, you're referring to the differences in post #1 and post#114. Sorry, skimming through the posts I misread#114. The MOI information then does not apply as I was applying it unless the swing speeds off the tee were to support that as well but that information is absent. It's possible that girl#2 is still swinging a bat with a lower MOI but swinging it faster off the tee than she is live, improving the batted ball speed and distance. If not, the MOI was less likely a culprit compared to pitch speed and contact point.

 

[Stever]

You won't like the answer.

If both swings reached 95mph just before impact, and one slowed to 50mph due to impact and the other slowed to 40mph due to impact, then the one that slowed to 40mph would hit the ball farther.

Why is this the case? Because the transfer of energy was more efficient.

The conservation of momentum states that "Mass x Velocity" (momentum) is conserved. So if going into impact the Velocity was 95mph, and leaving impact the Velocity was 40mph, then that loss of MV is transferred to the ball (... note that the Mass of the bat did not change, but the Velocity did change). The greater amount of momentum being transferred is rewarded with greater ball exit speed.

It isn't like the hitter tried to slow their bat down ... it's just that she is transferring energy more efficiently.

That's important ... the hitter should not be trying to slow their bat down through impact.

Yea, I cant seem to believe this.... How could the higher sustained speed not apply more Mass v Velocity to the ball. If the ball had feelings, I think it would tell us which swing hurt more. So if the swing generated 95mph before impact and kept up the 95mph through the collision, extension, and all the way to finish, it would not hit the ball further than the swing that slowed to 30mph at collision? (exaggerated example)

 

[Eric F]

Yea, I cant seem to believe this.... How could the higher sustained speed not apply more Mass v Velocity to the ball. If the ball had feelings, I think it would tell us which swing hurt more. So if the swing generated 95mph before impact and kept up the 95mph through the collision, extension, and all the way to finish, it would not hit the ball further than the swing that slowed to 30mph at collision? (exaggerated example)

That one isn't making sense to me, either. In my head (which is, admittedly, not always screwed on right) there would be energy lost in the deceleration of the bat that isn't transferred into the ball during impact. Maintaining a higher bat speed during impact means less energy lost in the bat, not more energy transferred to the ball.

 

[FiveFrameSwing]

Momentum Conservation Principle

 

[Stever]

I learned from playing the game, experimenting, and from great coaches here and there. Not really interested in these science projects, though I don't dismiss how things may really happen.

So your saying FFS, that the bat that slows to 30mph during compression will hit it further than the bat that would stay 95mph through the entire swing?

 

[Greenmonsters]

I learned from playing the game, experimenting, and from great coaches here and there. Not really interested in these science projects, though I don't dismiss how things may really happen.

So your saying FFS, that the bat that slows to 30mph during compression will hit it further than the bat that would stay 95mph through the entire swing?

IME, science and today's technology have provided indisputable proof and corrected misconceptions held by many, ex-players not excluded! One case in point - IMO its important to understand things well enough to be able to convincingly and accurately explain why kids with successful results need to put their -11 and -12 bats away and focus on improving their faulty mechanics to ensure that they have a better chance at being successful in the long run.