Question: Find the gravitational force between two objects. Use the fact that the gravitational attraction between particles of mass m1 and m2 at a distance r apart is Gm1m2/r2. Slice the objects into pieces, use this formula for the pieces, and sum using a definite integral.
What is the force of gravitational attraction between a thin uniform rod of mass M and length l and a particle of mass m lying in the same line as the rod at a distance a from one end?