High School Physics Practice Test

Velocity under constant acceleration builds up linearly: v = v0 + a t. Since the block starts from rest, v0 = 0. With a = 2.4 m/s^2 and t = 4 s, the velocity is v = 0 + (2.4)(4) = 9.6 m/s. So after 4 seconds the block moves at 9.6 m/s. This matches the idea that doubling the time doubles the velocity when acceleration is constant, so the other numbers would come from different times or accelerations.