Why is resistivity important in solving this problem?

[LAph]

In free space there are two masses:
- Metallic sphere of mass M, radius R and total charge equal to 0. It has also a resistivityρ.
- Metallic sphere of mass m, radius r and charge q.
The distance between the masses is D. We can assume r <<R<<D and m<<M. The masses start accelerating until they collide anelasticaly. Find the energy that has become heat.

My question is: Why do I need ρ to solve this problem?
My solution is basically finding the difference between the initial potential energy and the final, but i haven't used the resistivity.

 

[berkeman]

In free space there are two masses:
- Metallic sphere of mass M, radius R and total charge equal to 0. It has also a resistivityρ.
- Metallic sphere of mass m, radius r and charge q.
The distance between the masses is D. We can assume r <<R<<D and m<<M. The masses start accelerating until they collide anelasticaly. Find the energy that has become heat.

My question is: Why do I need ρ to solve this problem?
My solution is basically finding the difference between the initial potential energy and the final, but i haven't used the resistivity.

Welcome to the PF.

You probably need the resistivity of the first sphere because currents will likely flow as part of this process.

If you would like additional help with this schoolwork problem, please start a new thread in the Homework Help, Introductory Physics forum, and fill out the Template you are provided there. Thank you.