Question

When Maggie applies the brakes of her car, the car slows down uniformly from 15.0 m/s to

0.0 m/s in 18.8 m. How long does it take the car to stop?

Answer 1

Step-by-step explanation:

Given that,

Initial velocity, u = 15 m/s

Final velocity, v = 0

Time, t = 18.8 m

Let a is the acceleration of the car.

`v^2-u^2=2as\\\\a=(v^2-u^2)/(2s)\\\\a=((0)^2-(15)^2)/(2* 18.8)\\\\a=-5.98\ m/s^2`

Now using second equation of motion:

`18.8=15t+(1)/(2)* (-5.98)t^2\\\\t=2.574\ s,2.443\ s`

Hence, the time is 2.574 s and 2.443 s