Two charged particles are located on the x axis. The first is a charge +Q at x = -a. The second is an unknown charge located at x = +3a. The net electric field these charges produce at the origin has a magnitude of 2keQ/a2. Explain how many values are possible for the unknown charge and find the possible values.

2 narrow, flat metal plates are positioned vertically, 20.00 cm. The first plate has a positive charge with charge density σ=+630.0 mC/m2 and a second plate has an equal but opposite negative charge with charge density σ=-6300.0 mC/m2 . There are also two narrow, flat metal plates positioned horizontally, 30.00 cm apart, with the top plate given a negative charge, and the bottom plate given an equal but opposite positive charge, such that the electric potential of the bottom plate is 5.00 V higher than the top plate. A small sphere with a mass of m =64.35 g, and a charge of q =22.00 mC is attached to a narrow, stiff, massless, insulating rod with a length of L= 8.00 cm, which is pivoted at point O, which is 2.000 cm from the second plate. The sphere/rod unit is angled at 5 degrees with horizontal and released from rest. Will the sphere/rod ever hit an angle of 0 degrees with the horizontal? If so, how long will it take to reach that point?

Four identical charged particles (q +10.4 pC) are located on the corners of a rectangle as shown in the figure below. The dimensions of the rectangle are L 54.6 cm and W 14.7 cm L W (a) Calculate the magnitude of the total electric force exerted on the charge at the lower left corner by the other three charges. N (b) Calculate the direction of the total electric force exerted on the charge at the lower left corner by the other three charges. (counterclockwise from the x-axis)

A positively charged particle Q1=+25 nC is held fixed at the origin. A second charged Q2 of mass m=8.5 ug is floating a distance d=25 cm above charge Q1. The net force on Q2 is equal to zero. You may assume this system is close to the surface of the Earth.  b. Calculate the magnitude of q2 in units of nanocoulumbs.