gravity of rod on particle?

Question

In Fig. 13-41, a particle of mass m1 = 0.56 kg is a distance d = 30 cm from one end of a uniform rod with length L = 5.5 m and mass M = 2.4 kg. What is the magnitude of the gravitational force on the particle from the rod?

http://i95.photobucket.com/albums/l156/pontellierlover/fig13_41.gif

Answer 1

Set you equation as

dF= G m1 dm /(d + x)^2 0 dm= pdx

dF= G m1 pdx /(d + x)^2 0 where p=m2/L

Just do the definite integral