a 900 N running back moving at 2.0 m/s is stoppped in 0.70 seconds when hit by a lineback. What average foarce did the linebacker exert on the running back?

Question

How much did the running back's momentum change?

Answer 1

F = m*a
900N = m*(9.8m/s^2)
m = 91.8367 kg

a = (change in velocity) / (change in time)

a = (Vf - Vi) / (change in time)

a = (2 - 0) / (.7) = 2.85714 m/s^2

F = 91.8367 kg * 2.8571 m/s^2 = 262.391 N

Answer 2

change in momentum:

p = m*(change in velocity)

p = 91.8367 kg * (2 m/s) = 183.673 kg*m/s