A sparrow flies into your kitchen window. It was travelling at 30 mph. What happens? A truck drives into your kitchen window. It was travelling at 10 mph. What happens?
(i did mention that Im assuming same power applies) Does the flies have the same power as the truck? If it has then it will travel at 1000mph. And given that all racket are more or less the same size, then a flies as big as a truck travelling at 1000mph (even if its very2 light weight) will surely explode anything on its way.
A sparrow flying at 30 mph hits a shuttlecock. How fast does the shuttlecock rebound? A truck travelling at 10 mph hits a shuttlecock. How fast does the shuttlecock rebound? The physics of the situation is surprisingly complicated. Not all of the racket's momentum will be transferred to the shuttle. So the equation "more momentum = a more powerful shot" is simply not true. Unfortunately, right at this moment I can't figure out exactly how it ought to work. But I'm sure it's not so simple.
... there is a simple solution... rotational motion.... the further away from the center of mass from the pivot is, the more force the racket acts on the shuttle. so it will depend more on the strength of your arm (i.e the part of the arm between elbow and hand) than your wrist, therefore the same person can hit the shuttle harder with a lighter racket, if their relative strength of their wrist is stronger than their arm...
We can limit the complexity since we human being that have a limited strength. Lets not confuse ourself with balance point (which IMO will affect stability as well as gravitation), thats another topic. Lets assume that 2 rackets have the same bp. There is no question here that one can swing a lighter racket faster compare to the heavier one. 1 rock is 100g another is 101g, given everything else held constant, which one you can throw the furthest? And thats why if we look at the past, racket weight is getting less and less until it stop to a point where at the moment there is no suitable material as light and as strong/stiff as carbon. If there is one, i will have no doubt that we will go to that direction. And we will look back and wonder 89g racket was too heavy, the same way now we think of a wooden racket.
balance point is part of the question.... what do u mean by gravitation? lighter does not mean better, there are plenty of lighter rackets than say.. yonex's top range out there.... momentum before the collision must be equal to the momentum after the collision near the instant of collision, you can increase the speed, but there is a limit in which an arm can swing... you can't just keep making the racket lighter... and as always you can't violate the laws of physics... on the other side of the spectrum a human arm can only generate so much energy, so if the racket is too heavy the swing speed is too low to say... block a smash.... so a balance must be found...
In comparison to a head heavy racket, with light head racket you should be able to generate extra acceleration and hence speed.
Firstly we cant compare YY top range and those ligher rackets that are less stiff and therefore less powerful. I also understand your second point, and i agree with that. There will be a point where a reduction in weight is no longer adding any extra punch, but we have not explore the boudaries have we? How are we for certain know that a 50g racket is no better than a 80g racket? While we know that 89g racket is better than 110g racket.
get hold of a lighter racket, swing it and tell me how it feels.... if your 50g racket theory is true then why are the pros using 2U rackets and not just all rush to 3U rackets with an extra stiff shaft? Lin Dan used lead tape on his AT700 which adds a few grams on the already heavy 2U racket, taking it close to 100g, how does it fit in to your lighter the better theory? now back to your average badminton player, how in the world do you expect them to bend an extra stiff shaft with half the weight at the center of mass (which i may note is somewhere in the middle of the shaft)... you can't just throw out a statement saying 'we have not explore the boundaries" that just comes from thin air.... for all you know younex has tried it... (i.e the 4U version of AT700 and AT900 and i may note people prefer the 3U AT700 + there are 5U rackets out there)
We cant use pro as a single barometer. PSW for that matter was using NS9000X which is a head light and extra stiff. For the rest of us, I dont see a problem with bending an extra stiff shaft with half the weight. Assuming that the reduction in weight adds the extra speed, then at the moment of impact the force should be at least the same as if one is using a heavier racket. Lastly, the reason that fewer poeple prefer 5U or 6U is because they are not stiff enough and therefore the racket bends too much and slower than the arm swing.
