Two negative charges that are both - 5.0 x 10^-5 C push each other apart with a force of 15 N. How
far apart are the two charges?

What defines the mass number of an isotope? a. the sum of the neutrons and protons b. the sum of the neutrons and electrons c. the number of neutrons d. the number of protons

If you place a magnet under a clear dish, and sprinkle iron fillings over it, above what part of the magnet will most of the fillings gather

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?