Acar is travelling at a speed of 30 m/s. it decelerates at a rate of 12 m/s^2. calculate the time taken for the car to come to a rest.

The answer to your question is: t = 2.5 s

Explanation:

Data

vo = 30 m/s

a = -12 m/s2

t = ?

vf = 0 m/s

Formula

vf = vo + at

Substitution

                              0 m/s = 30 + (-12)t

Solve it for t           -30 = -12t

                              t = -30 / -12

                              t =  30/12  = 15/6 = 5/2

                              t = 2.5 s                              

it may be wrong but i think its a

it is a negative acceleration