A car starts from rest and after 20 seconds its velocity becomes 108 kmh. Find the acceleration of the car.

Expert Answers

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The formula of acceleration is:

`a = (Delta v)/(Delta t)`

where   `a` - acceleration      

         `Delta v` - change in velocity and

         `Delta t` - change in time

In the above problem, initial velocity is zero and the final velocity is 108 km/hr. So change in velocity is:

`Delta v = 108 - 0` `= 108 (km)/(hr)`

And the given change in time is 20 seconds. For the unit to be consistent, convert the seconds to hours.

`Delta t = 20 sec * (1 min)/(60sec)*(1hr)/(60 min) = 1/180 hr`

Then, substitute the values of `Delta v` and `Delta t` to the formula of acceleration.

`a =( Delta v)/(Delta t) = 108/(1/180) = 19440`

Hence, the accelearion of the car is 19,440 `(km)/(hr^2)` .

Approved by eNotes Editorial Team

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