Two charges of 2 C and 4 C are positioned on a line at points 5 and 2, respectively. What is the net force on a charge of 3 C at 1?

1 Answer
May 21, 2017

The forces on the 3 C charge due to each of the other charges can simply be added together.

The net force is F=k×2×362+k×4×332=1.35×1010 C

Explanation:

The charges in question are all positive, so the forces will be repulsive. The 3 C charge will be experiencing a force to the right, if we imagine the number line.

The distance from the 2 C charge to the 3 C charge is 6 m (we are not told the units of distance being used, but metres are the appropriate SI unit). The distance from the 4 C charge to the 3 C charge is 3 m.

The net force, then, is:

F=k×2×362+k×4×332

where k=9×109 Nm2C2

F=k×2×362+k×4×332=1.35×1010 C

This is a very large force, but these are very large charges, quite close together, and the constant is large.