Question

A driver traveling at 30.0 m/s presses the brakes decelerates at -8.80 m/s^2. How much time, in second, does it take her to come to a full stop?

Answer 1

It takes her 3.409 seconds to make a full stop.

Step-by-step explanation:

The time it takes to make a full stop can be determined by the equation of velocity for a Uniformly Accelerated Rectilinear Motion:

`v_(f) = v_(i) + at` (1)

Where
`v_(f)` is the final velocity,
`v_(i)` is the initial velocity, a is the acceleration and t is the time.

Equation (1) can be rewritten in terms of t:

`v_(f) - v_(i) = at`

`t = (v_(f) - v_(i))/(a)` (2)

For this particular case the final velocity will be equal to zero (
`v_(f) = 0`):

`t = (0 m/s - 30.0 m/s)/(-8.80 m/s^(2))`

`t = 3.409 s`

So it takes her 3.409 seconds to make a full stop.