1. A small plastic ball of mass 6.39 x 10-3 kg and charge +0.164 C is suspended from an insulating thread and hangs between the plates of a capacitor. The ball is in equilibrium, with the thread making an angle of 30.0° with respect to the vertical. The area of each plate is 0.01215 m2. What is the magnitude of the charge on each plate?

2. Identical point charges of +2.4 μC are fixed to diagonally opposite corners of a square. A third charge is then fixed at the center of the square, such that it causes the potentials at the empty corners to change signs without changing magnitudes. Find the third charge.

3. A charge of -4.39 μC is fixed in place. From a horizontal distance of 0.0132 m, a particle of mass 9.78 x 10-3 kg and charge -8.74 μC is fired with an initial speed of 90.4 m/s directly toward the fixed charge. How far does the particle travel before its speed is zero?

4. The drawing shows a uniform electric field that points in the negative y direction; the magnitude of the field is 4300 N/C. Determine the electric potential difference (a) VB - VA between points A and B, (b) VC - VB between points B and C, and (c) VA - VB between points C and A.