# hitting through the ball?

Discussion in 'Tennis Tips/Instruction' started by ishiun, Nov 7, 2013.

1. ### Topspin ShotLegend

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I would just stick to using the term racket speed. Technically correct and easy to understand.

The physics explanation (if interested) is as follows. Angular momentum must always be conserved unless additional energy is added (which is not happening here). Angular momentum is the product of mass, velocity, and the radius of the arc. The mass isn't changing, so we don't have to worry about it here. Therefore, if you shrink the radius, you increase the velocity. Thus, more racket speed.

Last edited: Dec 13, 2013
2. ### Tight LinesProfessional

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This is quite interesting. In practical terms, does this mean that for a given person, a double bend forehand generates more RHS than a straight arm forehand? If so, why are so many people trying to copy Federer?

Harry

3. ### arche3Banned

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Like when an ice skater pulls their arms in while spinning in circles they spin faster. Same idea.

4. ### Topspin ShotLegend

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I'm not sure about this. First off, if you're locking the double bend structure in the backswing, there certainly will not be more racket speed. If you start with a straighter arm and bend it a bit as you swing forward, you might get a boost, but there are other things to consider as well. Quite possibly, the physical advantage you would get could be canceled by something biomechanical. Honestly, I have no idea.

Exactly.

5. ### user92626Legend

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No, it should be the other way around. As Topspin puts it: Angular momentum is the product of mass, velocity, and the radius of the arc.

If mass and velocity stay the same but you increase the radius as in extending your arm longer, there'd be more momentum.

6. ### sureshsBionic Poster

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he was coming from an angular momentum viewpoint like skating or diving but I personally think they don't apply to tennis. no body spins enough for this to happen

7. ### sureshsBionic Poster

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I meant angular momentum conservation viewpoint