Force Exerted by Roads of Length x & Separation x - Physics Problem

[voko]

Good. Now that you know F(u) acting on a material point at x = u of mass m, let there be another rod between x = 2d and x = 3d, of mass m2. What is the net force?

 

[jingu]

Net force on point mass m? It will depend on the positions of m2 and m bcoz gravitational force is always attractive so there will be two cases ...please tell whether u > 3d...or d<u<2d

 

[voko]

Net force on the second rod from the first rod.

You know the location of the first rod: 0 ≤ x ≤ d. You know the location of the second rod: 2d ≤ x ≤ 3d.

You know the force from the first rod on a point at x = u.

 

[jingu]

I solved it I came up with this answer F= (GMm ln(4/3))/d^2...please verify...

 

[voko]

I get the same answer. Very good!

 

[jingu]

thank you very much...Are u sure that the answer is the same...?