Question

12. The brakes on a vehicle can slow it down at a rate of 15m/s 2. Remember that slowing down is also a rate of change of speed. If this vehicle is travelling at 40 m/s how long would it take the brakes to bring the vehicle to a standstill? Show all steps and formulae used​

Answer 1

Explanation:

there are several formulas that could play a role.

but in our case, where we have velocities and the deceleration, we are going to use

fV = iV + at

fV = final velocity (0 on our case)

iV = initial velocity (40 m/s in our case)

a = acceleration (-15 m/s² in our case)

t is the time it takes to reach fV.

0 = 40 + (-15)t = 40 - 15t

15t = 40

3t = 8

t = 8/3 = 2.666666666... seconds

so, it takes 2.6666666... or 2 2/3 seconds to bring the vehicle to a standstill.