# The speed of leptons

1. Nov 6, 2008

### Lok

What would the speed of a quark in a nucleon be? I know they are bound by the strong force to a triangular shape, but to an outside observer they must show some movement, or the triangular structure as a whole should. What is it's speed ( average for room temperature )?

Last edited: Nov 6, 2008
2. Nov 6, 2008

### malawi_glenn

You can find the "speed" by doing the same calculation as you would have done in finding the speed for an electron in an atom. Start from the heisenberg uncertantiy realation for instance, take the size of the nucleon, 1fm, and then you'll get the order of magnitude of momentum. Then mass of quark is approx 5MeV/cÂ². There are other ways in doing this of course, which can give you an approximate value of the speed.

3. Nov 6, 2008

### ZapperZ

Staff Emeritus
Just out of curiosity, what does this have anything to do with "the speed of leptons"?

Zz.

4. Nov 6, 2008

### Lok

It was about quarks ... but i was a little confused for a bit... then i edited the post but the title remained.

Tx for the formula. Is there any geometrical view on their motion though. There must be a reason for the inabillity to create 4(and beyond) quark particles, and the condition seems geometrical in nature.

5. Nov 6, 2008

### malawi_glenn

It has to do with the colour charges of the quarks, and colour confinement.