Two identical charged particles of mass m=1.6 kg and electric charge Q=-5.2 μC are placed on an frictionless 26° incline. One of them falls down to the bottom and stops against the wall. The other stays at rest in the middle of the incline as shown in Figure. Find is the distance between the particles.

1 answer

The charged particle on the incline stays in the middle because the electrstatic force of repulsion balances the gravitational force acting along the incline downwards.

If the distance between the charged particles is x:

k Q^2/x^2 = mg*(sin21deg)

here k =1/4*pi*epsilon0
Compute x from the above expression.