Question

A car traveling at 30 m/s starts to decelerate steadily. It comes to a complete stop in 9 seconds. What is its acceleration?

Answer 1

To calculate the acceleration we use the formula,

`a=(v_(f)-v_(i)  )/(t)`

Here,
`v_(f)` is the final velocity of the car and
`v_(i)` is the initial velocity of the car and t is time .

Given
`v_(i) =30 m/s` and
`t= 9 s`.

The final velocity
`v_(f) =0` , because car comes to stop.

Substituting these values in above formula we get,

`a=(0 m/s-30m/s)/(9)`

`a=3.3 m/s^(2)`

Here, acceleration is negative because car is decelerated.