Question

A car of mass 1ton is brought to rest from a speed of 40m/s in a
distance of 80m. Find the braking force of the car assuming that it is
constant and that there is a constant resistance to motion of 100N.

Answer 1

Answer:

10,100 N

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