Electric Field Question?

Question

This is the question as written in the textbook. If anyone can give me some insight about the solution, or just a general direction to proceed, please let me know.

A proton orbits a long charged wire, making 1.0 x 10^6 revolutions per second. The radius of the orbit is 1.0cm. What is the wire's linear charge density?

Thanks again.

Answer 1

Here the problem is asking you to equate the centrifugal force the proton would feel and the electric force the wire would exert on the proton at a distance of 1.0 cm

Thus   [ (mass proton) (velocity of proton)^2 ] / radius of orbit

                                            = The force exerted by an infinitely long

                                               wire on a proton at a distance of r

The solution of charge density from this equation should give you the required answer.