GMAS Physical Science Practice Test

Acceleration describes how velocity changes over time. Velocity isn’t just how fast something moves; it also includes direction. If either the speed or the direction changes, the velocity is changing, and the rate of that change is acceleration (a = Δv/Δt). This is why speeding up, slowing down, or turning all involve acceleration. The other terms don’t capture this idea: speed only tells how fast, not how velocity evolves; mass is the amount of matter; friction is a force that can cause motion to change but isn’t the rate of velocity change itself.