Average acceleration and displacement

Question

The cheetah can reach a top speed of 114 km/h (71 mi/h). While chasing its prey in a short sprint, a cheetah starts from rest and runs 45 m in a straight line, reaching a final speed of 72 km/h.

(a) Determine the cheetah’s average acceleration during the short sprint, and

(b) find its displacement at t = 3.5 s.

Answer 1

Since s = 1/2*a*t^2 and v = a*t, it follows (using algebra) that a = v^2 / (2*s). Always use the base equations!