3609801
The bartender says,"we don't serve tachyons here."

A tachyon walks into a bar.

3609818
Why are quantum physicists so poor at sex?

Because when they find the position, they can't find the momentum, and when they have the momentum, they can't find the position.

10 Jokes Only Engineers Will Understand

3627847 I didn't get this one:

7. Knock knock. Who's there? Interrupting coefficient of friction. Interrupting coefficient of fri.... mmmuuuuuuuuuuuuuuuu (μ)

3628156
The symbol for the coefficient of friction between two surfaces is the Greek letter mu (μ)

It's a parody of the old 'interrupting cow' joke.

3628286 I still don't get it. I also don't know about the cow joke.

3628346
http://en.wikipedia.org/wiki/Friction#Coefficient_of_friction

Knock Knock
Who's there?
Interrupting cow.
Interrupting co-MOOOOOO!

3628374 Yes! That did it for me. I get it now. The colors helped. Thanks.

3628386
Always happy to help.