PhysicsChange in Angular Momentum
posted by Anthony .
What is the change in angular momentum of a planet with radius R if an asteroid mass m and speed v hits the equator at an angle from the west, 40 degrees from the radial direction?

Angular momentum about the spin axis is conserved. The planet with added asteroid will gain angular momentum equal to that of the asteroid before collision. You have not said what the initial planet mass or angular momentum was.
Angular momentum change = m*v*R*sin40
It can be either an increase ior decrease depending upon the direction the planet was originally spinning. 
The planet has mass M and is spinning in a counterclockwise direction. I know the asteroid will increase the momentum of the planet, so the total change in angular momentum is equal to positive. m*v*R*sin(40) ?