Two tiny, spherical water drops, with identical charges of -4.79 × 10-16 C, have a center-to-center separation of 0.999 cm. (a) What is the magnitude of the electrostatic force acting between them? (b) How many excess electrons are on each drop, giving it its charge imbalance?

Sphere A having a net charge of +2.50E-6 C is placed on a scale, which measures its weight in Newtons. Sphere B having a net charge of –6.40E-6 C is directly positioned 5.58 m above the first sphere, and the reading of the scale is found to be zero. What is the mass of sphere A (in kg)?

Common transparent tape becomes charged when pulled from a dispenser. If one piece is placed above another, the repulsive force can be great enough to support the top piece's weight. Assuming equal point charges (only an approximation), calculate the magnitude of the charge if electrostatic force is great enough to support the weight of a 16.3 mg piece of tape held 0.64 cm above another. (The magnitude of this charge is consistent with what is typical of static electricity.) (C)

Sphere A having a net charge of +2.50E-6 C is placed on a scale, which measures its weight in Newtons. Sphere B having a net charge of –6.40E-6 C is directly positioned 9.79 m above the first sphere, and the reading of the scale is found to be zero. What is the mass of sphere A (in kg)?   On the x axis, a point charge Q = +4.55E-6 C is placed at the origin x = 0.00 m. What is the electric field E at x = –5.51 m (in N/C; use positive sign if E points in the +x direction, and negative sign if E points in the –x direction)?