Himanshu tries to calculate the force exerted by 2 spherical objects of radius 1m each, having charges 3C and 5C and travelling at 4m/s with respect to each other. At an instant when the separation between them is 10 m, Himanshu theoretically calculates the force exerted by the one on another. He only applies Coulomb's law and let us assume that he manages to apply it correctly but gets his answer wrong. Possible explanations could be?
All of these
Coulomb's law works only for static point charges. When large sized charge distributions are involved, we might need integration. Also when charges are in motion, they produce another kind of field called magnetic field which in turn exerts magnetic force on a moving charge particle. So Coulomb's law only gives a part of the force.
Note: It is not claimed that the spheres are conductors. In the case of spherical conductors, uniformly charged non-conducting sphere or shell, the electrostatic force for a point outside will be similar to that of a point charge of equal magnitude kept at their centres.