At the start of his race, an 88-kg runner pushes against the starting block, exerting an average force of 1700 N . The force that the block exerts on his foot points 20∘ above the horizontal.Determine the horizontal speed of the runner after the force is exerted for 0.34 s .
F = m * a 1700 N = 88 kg * a a = 1700 : 38 a = 19.318 m / s² v = a * t = 19.318 m/s * cos 20° * 0.34 s= = 19.318 m/s² * 0.93969 * 0.34 s = =18.15 m/s² * 0.34 s = 6.171 m/s Answer: The horizontal speed of the runner after the force is exerted for 0.34 s is 6.171 m/s.
