Question

An 80 kg man starts from rest and after 3.50 seconds is running at a speed of 12.0 m/s. The force needed for this man to get up to this speed in 3.50 seconds is ____ N.

Answer 1

Assuming he has a constant acceleration you can use the kinematic equation:\[V_f=V_i+at\]\[12.0m/s=0m/s + a(3.50s)\]\[a=3.43m/s^2\]Now that you know the acceleration, you can use:\[F=ma=(80kg)(3.43m/s^2)=274.4N\]

Answer 2

Note that taking into account significant figures, that answer becomes simply 274N.

Answer 3

Thank you, makes more sense now.

Answer 4

np :)