# Tennis Racquet

1. Sep 21, 2007

### anirudhreddy

Could you guys please tell me a very lab-doable method for finding the tension of the strings of a tennis racquet?
thx

2. Sep 21, 2007

### Gokul43201

Staff Emeritus
Does it have to be non-destructive?

3. Sep 21, 2007

### anirudhreddy

Yup. i play tennis with that racquet

4. Sep 21, 2007

### rcgldr

I don't think it can be done via an algorithm. You'd have to actually restring a racquet with various tensions and then measure how much the strings flex when a force is applied to the center of the racquet and curve fit the results. Even this may change over time due to friction and wear of the strings.

I'm also not sure if the strings "relax" after the initial stringing of a racquet. Players find a stringing tension they like and stick with that. Current racquets, the new polyester strings, and stringing machines are pretty accurate compared to older times when you could see players bouncing the edge of a racket against the strings of another racquet to choose which one to play with.

5. Sep 22, 2007

### Danger

If you know the mechanical properties of the 'head', be it wood, fibreglas, carbon fibre, or whatever... maybe you can do distortional measurements with and without the strings to see how much deformation they cause?
From the other end, if you know the physical properties of the strings themselves, you can perhaps do deformation measurements of the 'web?' under various load conditions.
I'm just pulling stuff out of my ass here, though, because I really don't know anything about the subject.

6. Sep 24, 2007

### Meir Achuz

1. Pluck the string, and measure the frequency of vibration. Then use physics.
2. Clamp the string. Measure the force required to pull it the slightest amount.
Compare.

7. Sep 24, 2007

### HallsofIvy

Drop a tennis ball on the strings. Measure how high it goes. Of course, you would have to compare it to the bounce on a racket with known tension.