- #1
srhelfrich
- 7
- 0
In kinetic theory, the number of molecules hitting a unit area of a surface per unit time with speeds between v and v + dv and angles between \theta and \theta + d \theta is found to be a function of sin(theta) and cos(theta). There will often be a practice problem asking to show that the average value of cos(theta) for these molecules is 2/3.
My question is why the expected value wouldn't be zero instead of 2/3? What is the significance of finding this average value?
My question is why the expected value wouldn't be zero instead of 2/3? What is the significance of finding this average value?