A car starts from rest, then accelerates at 1.20 m/s^2 for 7.00 s. It hits the brakes, slowing to stop at a rate of -4.25 m/s^2. What is the total time for the problem? (Unit = s) PLEASE HELP!!

Explanation:

First part of the journey;

If the car starts from rest, then accelerates at 1.20 m/s^2 for 7.00 s, the total time taken during this period is 7.0s.

But then  lets get the velocity v of the car during its first part of the journey.

Using the formula v1 = u1+ at1

v = 0+1.2(7)

v = 8.4m/s

Second part of the journey is when the driver hits the brake and slowing to stop at a rate of -4.25 m/s^2. To calculate the time it takes by the body to decelerates, we will use the equation of motion v2 = u2 + at2

v = final velocity of the car during the second part of the journey

u = initial velocity of the car during the second part of the journey

a = deceleration

t = time taken

Given v2 = 0m/s, u2 = 8.4m/s, a = -4.25m/s²

0 = 8.4-4.25t2

4.25t2 = 8.4

t2 = 8.4/4.25

t2 = 1.98secs

Total time taken for the journey = t1+t2

= 7.0s + 1.98s

= 8.98secs

The Reconstruction implemented by Congress, which lasted from 1866 to 1877, was aimed at reorganizing the Southern states after the Civil War, providing the means for readmitting them into the Union, and defining the means by which whites and blacks could live together in a nonslave society.