Answer:
KE = F * S initial kinetic energy will expended in stopping object
1/2 M V^2 = F * S
S = 1/2 * 50 * 35^2 / 800 = 38.3 m stopping distance
If you need to know the stopping time involved -
(V2 - V1) = a t where the change in velocity is 35 m/s
a = F / M = 800 / 50 = 16 m/s^2 deceleration of mass
t = 35 / 16 = 2.2 sec
