A ball (mass of 0.5kg) is suspended on a string that is attached to the ceiling. The ball is charged with an unknown charge q. Determine the magnitude of the charge on the ball if the electric field strength is 2000N/C, and the string forms an angle of θ = 30° as diagrammed below. HINT: Create a free body diagram.

Question

A ball (mass of 0.5kg) is suspended on a string that is attached to the ceiling.  The ball is charged with an unknown charge q.  Determine the magnitude of the charge on the ball if the electric field strength is 2000N/C, and the string forms an angle of  θ = 30° as diagrammed below.  HINT: Create a free body diagram.

R_scott · Answer

no diagram

the 30º angle makes the most sense with the ceiling

so the horizontal string force is ... m g sin(Θ)
... this is equal to the force of the electric field on the ball

force = field strength * ball charge