Answer: a) 8.2 * 10^-8 N or 82 nN and b) is repulsive
Explanation: To solve this problem we have to use the Coulomb force for two point charged, it is given by:

Replacing the dat we obtain F=82 nN.
The force is repulsive because the points charged have the same sign.
Answer:
Explanation:
Check the attachment for solution
Reaction force/support force/ lift/ buoyancy/ weight depends on situation
Answer:
Each piece will have a north pole and a south pole
Explanation: