Question

A car traveling at `7.0` `m``/``s` accelerates uniformly at `2.5` `m``/``s^2` to reach a speed of `12.0``m``/``s`. How long does it take for this acceleration to occur?

Answer 1

2 seconds

Explanation:

initial speed `u=7 ms^-1`
Final speed `v =12 m s^-1`
acceleration (uniform) `a=2.5 ms^-2`

using First equation of motion

`v=u+at`

Substituting

`12=7+2.5t`
`12-7=2.5t`
`5=2.5t`
`t=2 s`