When starting a foot race, a 70.0-kg sprinter exerts an average force of 650 n backward on the ground for 0.800 s. what is his final speed?

Given:

m = 70 kg, mass

F = 650 N, force

t = 0.8 s, time

Calculate the acceleration.

a = F/m = (650 N) / (70 kg)

= 9.2857 m/s²

Because the initial velocity is zero, the final velocity (after time 0.8 s) is

v = a*t = (9.2857 m/s²) * (0.8 s)

= 7.43 m/s

Answer: 7.43 m/s (nearest hundredth)