- #1
redivider
- 8
- 2
Homework Statement
Calculate the gravitational force between a point mass and a circular platform.
Homework Equations
G=m1*m2/r^2
The Attempt at a Solution
http://i.imgur.com/dfZf9GK.jpg
The actual solution is different. They integrated by the angle between a/r (alpha) but i do not understand the cos(alpha) at the start, check this out:
http://i.imgur.com/nwxhCEb.jpg
Can anyone explain this please? Thanks.