Question

A car moving with an initial speed of 25 m/s slows down to a speed of 5 m/s in 10 seconds Calculate a) the acceleration of the car.? b) the distance covered by the car

Answer 1

(a) The acceleration of the car is,
`-2m/s^2`

(b) The distance covered by the car is, 150 m

Explanation :

By the 1st equation of motion,

`v=u+at` ...........(1)

where,

v = final velocity = 5 m/s

u = initial velocity = 25 m/s

t = time = 10 s

a = acceleration of the car = ?

Now put all the given values in the above equation 1, we get:

`5m/s=25m/s+a* (10s)`

`a=-2m/s^2`

The acceleration of the car is,
`-2m/s^2`

By the 2nd equation of motion,

`s=ut+(1)/(2)at^2` ...........(2)

where,

s = distance covered by the car = ?

u = initial velocity = 25 m/s

t = time = 10 s

a = acceleration of the car =
`-2m/s^2`

Now put all the given values in the above equation 2, we get:

`s=(25m/s)* (10s)+(1)/(2)* (-2m/s^2)* (10s)^2`

By solving the term, we get:

`s=150m`

The distance covered by the car is, 150 m