In the picture below, half of Earth is experiencing day, and half is experiencing night. If the Sun is always giving off light, why do we not all experience day all the time? In your own words, explain why we have a cycle of light and dark that repeats every 24 hours in most parts of the world.

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?