Question

A car accelerates from rest to a velocity of 5 meters/second in 4 seconds. What is its average acceleration over this period of time? A. Its acceleration is 1.25 meters/second. B. Its acceleration is 5 meters/second. C. Its acceleration is 0.8 meters/second. D. Its acceleration is 1.25 meters/second2. E. Its acceleration is 20 meters.

Answer 1

The average acceleration is

`\bar a=(5\,(\mathrm m)/(\mathrm s)-0\,(\mathrm m)/(\mathrm s))/(4\,\mathrm s)=1.25\,(\mathrm m)/(\mathrm s^2)`

Answer 2

The acceleration of the car is
`a=1.25\ m/s^2`.

Step-by-step explanation:

It is given that,

Initial speed of the car, u = 0

Final speed of the car, v = 5 m/s

Time, t = 4 s

We need to find the average acceleration over this period of time. It is given by the rate of change of velocity. It is given by :

`a=(v-u)/(t)`

`a=((5-0)\ m/s)/(4\ s)`

`a=1.25\ m/s^2`

So, the acceleration of the car is
`a=1.25\ m/s^2`. Hence, the correct option is (D).