Question

car travels with a uniform velocity of 20ms^-1. the driver applies the brakes and the car comes to rest in 10 seconds calculate the retardation​

Answer 1

v=u+at

the final velocity becomes zero (0)

then ,

0=20^-1+10a

a= 2m/s^-1

Answer 2

Solution

As per the given data ,

• Initial velocity of the car = 20 m/s

• Final velocity of the car = 0 m/s ( as the car comes to rest )

• Time taken by the car to come to rest = 10 s

We can easily solve this question by using first equation of motion ,

⟹ v = u + at

On rearranging ,

⟹ a = v-u / t

Now let's substitute the given values in the above equation ,

⟹ a = 0 - 20 /10

⟹ a = -  20 / 10

⟹ a = - 2 m/s ²

(Negative sign denotes retardation)

The acceleration of the car is 2 m/s ²