A car that weighs 15,000 N is initially moving at 60 km/hr when the brakes are applied. The car is brought to a stop in 30 m. Assuming the force applied by the brakes is constant, determine the magnitude of the braking force

1 answer

60 km/hr = 60000m/3600s = 50/3 m/s

so,
v = 50/3 - at
t = 50/(3a)

s = 50/3 t - 1/2 at^2
= (50/3)(50/(3a)) - (1/2)(a)(50/(3a))^2 = 30
a = 125/27

F = ma = (15000/9.8)(125/27) = 7086 N

as always, check my math