Hunter’s velocity was 4.5 m/s. at the end of his race, his velocity was the same. which best describes his movement? his movement stopped. his acceleration is zero. his time was constant. his acceleration was positive.

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.