Answer:
10,100 N
Step-by-step explanation:
m - 1 ton = 1,000 kg
v₀ = 40 m/s, v = 0
d = 80 m
f = 100 N
Net force = F + f = ma
v² - v₀² = 2ad, so a = (v² - v₀²)/(2d) = (0 - 40²)/(2*80) = -10 m/s²
F = ma - f = 1,000*(-10) - 100 = -10,100 N
negative sign means opposite to the driving direction