World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s^2 .
part a
how much horizontal force f must a sprinter of mass 64 kg exert on the starting blocks to produce this acceleration?
express your answer in newtons using two significant figures.
part b
which body exerts the force that propels the sprinter, the blocks or the sprinter?
which body exerts the force that propels the sprinter, the blocks or the sprinter?
the blocks
the sprinter

Abasketball star covers 2.65 m horizontally in a jump to dunk the ball. his motion through space can be modeled precisely as that of a particle at his center of mass. his center of mass is at elevation 1.02 m when he leaves the floor. it reaches a maximum height of 1.90 m above the floor and is at elevation 0.910 m when he touches down again. (a) determine his time of flight (his "hang time"). (b) determine his horizontal velocity at the instant of takeoff. (c) determine his vertical velocity at the instant of takeoff. (d) determine his takeoff angle. (e) for comparison, determine the hang time of a whitetail deer making a jump with center-of-mass elevations yi = 1.20 m, ymax = 2.45 m, and yf = 0.750 m.