Question

4. A sports car accelerates from rest to a final velocity of 64 m/s at a rate of 12.3

m/s2. How much time did it take the car to reach its final velocity?
A. 3.7 s
B. 4.8 s
C. 4.9 s

Answer 1

`t = 5.2\ s`

Explanation:

Given

`a= 12.3m/s^2` --- acceleration

`v = 64m/s` --- final velocity

`u =0m/s` --- initial velocity (it is 0, because the car starts from rest)

Required

Determine the time taken

This will be solved using Newton's first equation of motion:

`v = u + at`

Substitute values for v, u and a

`64 = 0 + 12.3*t`

`64 = 12.3t`

`12.3t = 64`

Make t the subject

`t = (64)/(12.3)`

`t = 5.2\ s`

Hence, the time taken is approximately 5.2 seconds