- #1

icecats

- 5

- 0

## Homework Statement

I am working on the derivation of Kepler's Second Law based on torque and angular momentum. I understand that the vector "L" is equal to the mass (m) times the cross product of the vector "r" and the vector "v." The source I am following then states that

L = mrv

_{theta}. I do not understand how the source is deriving this from the cross product. This is shown in the second to last step on this web page.

## Homework Equations

L= r cross p

## The Attempt at a Solution

I am able to get to the point of computing the cross product, but no further. In other words, I have completed the algebra to arrive at L= m(r cross v).