Question

what best describes acceleration

Answer 1

Any change of speed or direction of motion.

Answer 2

velocity per second

Answer 3

Acceleration = Force/Mass
Acceleration is also described as a change in velocity. You can be going north at a constant of 45mph and your acceleration would be 0, as your velocity has not changed, but if you continued at 45mph one second, and 46 the next, continuing to accelerate at 1mph hour, you accelerate at 1mph per second, but velocity is different. velocity depends on other things too, but acceleration is like adding 5mph to your speed over a period of time.