What is final velocity of a 400kg car traveling at 36m/s that undergoes a braking force of 600N for 8 seconds

M = 400kg

u = 36 m/s

F = 600 N

t = 8s

first we'll calculate acceleration : -

⇒ F = ma

⇒ 600 = 400 * a

⇒ a = 3/2 = 1.5 m/s²

Now using, let v be the final velocity

⇒ v = u + at

⇒ v = 36 + 1.5 * 8

⇒ v = 48 m/s

Before the brakes are applied, the car's momentum is

Momentum = (mass) x (speed) =

(400 kg) x (36 m/s) = 14,400 kg-m/s.

The brakes deliver an ' impulse ' of

Impulse = (force) x (time) = (600 N) x (8 sec) = 4,800 kg-m/s.

The car's final momentum is (14,400 - 4,800) = 9,600 kg-m/s.

Momentum = (mass) x (speed)

9,600 kg-m/s = (400 kg) x (speed)

Divide each side by (400 kg) : Speed = 9600 kg-m/s / 400 kg = 24 m/s.