Great Jack Kramer says lighter racquet so more power

[5263]

and here was the whole point-

"Therefore, if a light racket allows you to swing faster, you will be able to hit harder.
Unfortunately, these equations can still not tell you, what racket you should use.
In order to draw more conclusion from this, one would need to know more on the bio-mechanical background: Can the body rather move heavier things slow or light things fast? What feels more comfortable and which speed can be coordinated best? How does performance drop over the course of a match? At what point does racket weight get in the way of your mechanics?"

[Timbo's hopeless slice]

Originally Posted by 5263

and here was the whole point-

Conclusion:
Heavier rackets provide more power

"Therefore, if a light racket allows you to swing faster, you will be able to hit harder.
Unfortunately, these equations can still not tell you, what racket you should use.
In order to draw more conclusion from this, one would need to know more on the bio-mechanical background: Can the body rather move heavier things slow or light things fast? What feels more comfortable and which speed can be coordinated best? How does performance drop over the course of a match? At what point does racket weight get in the way of your mechanics?"

fixed it for you

basically, the fact remains that, for a given swing speed, heavier racquets hit harder.

How fast an individual can actually swing one, of course, is by far the most significant variable...

[boramiNYC]

Originally Posted by Timbo's hopeless slice

there you go, it's simple!!!

Thanks slice, that made a lot of sense. I agree with that poster's conclusion and it seems the not too uncommon advice of 'heaviest racquet you can swing fastest' is a pretty accurate answer. But, at some point maneuverability and individual game style also become factor.

[boramiNYC]

Originally Posted by sureshs

So any analysis using conservation of momentum is wrong.

I'd think the conservation of momentum is pretty universal and it should apply as well. But, definitely not the only model that can explain this collision.

[SystemicAnomaly]

For a given swing speed, a heavier racquet or one with a higher swingweight, in general, should produce more power. Perhaps we should be talking about swingweight rather than static weight here:

http://twu.tennis-warehouse.com/lear...csandspeed.php

As suresh and others have indicated, rackets are typically 5 to 6x the mass of the ball. The assumption that the racket does not lose speed due to impact simply is not true. When a ball bounces on the ground, however, we can assume that the Earth does not lose too much speed due to the collision. TWU physicist, Rod Cross and others indicate that the angular velocity of the racket drops significantly. Here is another physics link that shows this:

http://www.science-animations.com/su...les/tennis.swf

This animation comes from the following page on tennis biomechanics:

http://www.science-animations.com/tennismechanics.html
.

[sureshs]

Originally Posted by boramiNYC

I'd think the conservation of momentum is pretty universal and it should apply as well. But, definitely not the only model that can explain this collision.

I edited my post.

But no, being universal has nothing to do with satisfying the condition under which it is universal.

[boramiNYC]

Originally Posted by SystemicAnomaly

TWU physicist, Rod Cross and others indicate that the angular velocity of the racket drops significantly. Here is another physics link that shows this:

http://www.science-animations.com/su...les/tennis.swf
.

This must be what creates the feel of 'plow through'. Less velocity drop from impact.

However, since the velocity just before contact is most important, the velocity drop shouldn't matter too much.

[boramiNYC]

Originally Posted by Timbo's hopeless slice

basically, the fact remains that, for a given swing speed, heavier racquets hit harder.

How fast an individual can actually swing one, of course, is by far the most significant variable...

More importantly how fast an individual can actually swing one 'with control' would be key.

[theblueark]

Originally Posted by gameboy

(m1 * v1) + (m2 * v2) = (m1 * u1<speed after collision>) + (m2 * u2)

If you know the v1 and v2 (initial velocity of ball and racquet), you can solve for u1 and u2. And when there is a great difference between the mass of one object (racquet + body weight) over the other (tennis ball), the equation for u1 and u2 simplifies to this:

u1 (racquet head speed after collision) = v1 (racquet head speed before collision)

In a reflex volley or block volley, let us assume the racquet is essentially not moving.

In your model because you assume u1 = v1, both racquets will stay dead where it is at contact due to out body holding onto the racquet in a death grip and u2 will = v2?

[gameboy]

Originally Posted by Timbo's hopeless slice

fixed it for you

basically, the fact remains that, for a given swing speed, heavier racquets hit harder.

How fast an individual can actually swing one, of course, is by far the most significant variable...

This is true, but you WILL swing a lighter racquet faster, so you will get more power from a lighter racquet (all other things being equal).

Which is why Jack is correct.

[gameboy]

Originally Posted by theblueark

In a reflex volley or block volley, let us assume the racquet is essentially not moving.

In your model because you assume u1 = v1, both racquets will stay dead where it is at contact due to out body holding onto the racquet in a death grip and u2 will = v2?

Yes, minus coefficient of restitution.

[Cheetah]

Originally Posted by gameboy

This is true, but you WILL swing a lighter racquet faster, so you will get more power from a lighter racquet (all other things being equal).

Which is why Jack is correct.

With all respect, i'll ask again... do you play tennis?

Because if you did you would know that heavier racquets hit more powerful shots (within reasonable limits). It's not even debatable. It's extremely obvious to anyone who's put lead on their racquet.

Yes you cherry pick outliers and say a child can swing faster with a 10oz stick vs a 17oz stick therefore blah blah blah etc etc... but those of us who've actually played with more than one racquet know the deal.

And Jack was probably speaking about light metal racquets in relation to the wood racquets at the time.

[gameboy]

I play tennis. Do you know physics? Last time I checked tennis still observes every physical law in the universe, including conservation of momentum.

Your argument may have been satisfactory in Middle Ages, but we have advanced a bit since then.

If we are just talking about what it "feels" to you, then it is a moot point since everyone is correct, including Jack.

But physically and mathmatically, what Jack is saying is true. You can deny it all you want, but it does not change the facts or how this world works.

[olliess]

(With regard to the mass of the ball being too large to ignore):

Originally Posted by gameboy

Can you link to the papers? I have read a lot of physics papers related to tennis and I have not read this...

Some analyses of the influence of mass on the racket-ball impact, along with discussion of the effect on racket speed by decreasing mass, are carried out in:

Cross, R. (2001), Customising a tennis racket by adding weights. Sports Engineering, 4: 1–14.

Cross, R. and Bower, R (2006), Effects of swing-weight on swing speed and racket power. Journal of Sports Sciences, 24(1): 23–30.

[theblueark]

Originally Posted by gameboy

Yes, minus coefficient of restitution.

You must be living in some alternate universe then. In the universe I'm from, even if I hold the racquet as tightly as I can facing up, and simply drop a ball onto it, the racquet is going to move backwards.

If in your universe the ball will not be able to move the racquet back a single millimeter, then I grant that you are correct, and I'd be playing tennis with a badminton racquet in a cartoon world.

Guys, his whole model is based on the assumption that the ball is insingnificantly light, and that it cannot move the racquet a single millimeter due to our massive body holding on to it. A flawed premise leading to a flawed model.

Every book on the physics of tennis shows a freely suspended racquet, not one clamped to death.

[Power Player]

I have 2 pure drives. One a Roddick and one a standard plus. after some slight mods, the Roddick weighs 345 and the Standard weighs 325.

Having spent 9 hours using both I clearly hit a bigger ball with the heavier one, since I wanted to choose between the 2 in terms of what works for me. The 325 gram stick still hits pretty big, but I wanted more depth and heaviness.

So without dropping math and science, I will just use a real world tennis example. Heavier stick hits a heavier ball.

Also, did gameboy really say 1 ounce does not make a difference??"?

[OTMPut]

Conservation of momentum holds only when there are no non-conserving forces (e.g. friction) in action.

Stiffness is as important as mass. Lighter stiff could be > heavier flexible.

[Power Player]

You are right about stiffness.

I think that is why the PDR hits such a massive ball. It is right at 12ozs, which is a nice weight, but it also is stiff AND has the thick beam.

So there are many factors. Very stiff racquets at a lighter weight can hit bigger than their specs, but the lighter you go the less shock is absorbed so you have to be more careful.

[Limpinhitter]

Originally Posted by Power Player

I have 2 pure drives. One a Roddick and one a standard plus. after some slight mods, the Roddick weighs 345 and the Standard weighs 325.

Having spent 9 hours using both I clearly hit a bigger ball with the heavier one, since I wanted to choose between the 2 in terms of what works for me. The 325 gram stick still hits pretty big, but I wanted more depth and heaviness.

So without dropping math and science, I will just use a real world tennis example. Heavier stick hits a heavier ball.

Also, did gameboy really say 1 ounce does not make a difference??"?

FYI, your experience seems logical. But, according to TWU's power comparison tool, the PD+ is more powerful than any of the PD, PDR and PDR+. You can check it out here: http://twu.tennis-warehouse.com/cgi-...eruniverse.cgi

PS: I am referring to the PD GT's, not the latest 2012 models which are not all available on the comparison tool.

[Power Player]

Thats why I never can use those tools. I use my own personal experience, and I can assure you that is not the case.

The PD+ is powerful though.

Here is the thing..a standard racquet comes through the air very fast compared to a plus. So even though the PDR is heavier, I can swing it faster..so fast that I added lead at 3 and 9.

So while maybe the PD+ reacts better if you shoot a ball off it's strings or whatever they do..if you are a power hitter and take both of those sticks out to the courts, you will experience what I did. More racquet head speed with the PDR, plus the weight will equal a more powerful ball with more spin and heaviness to it as well.