Question

the speed of car is reduced from 90km/hr to 36km/hr in 5s ​

Answer 1

Here,

Initial velocity of the car(u) = 90km/hr.

Final velocity of the car(v) = 36km/hr.

Time taken by the car(t) = 5 seconds.

Retardation = ?

Acceleration

= (Final velocity - Initial velocity)/ Time

= (v - u) / t.

= { (36 - 90) /5 }ms^-2.

= -54/5ms^-2.

= -10.8ms^-2.

So, the retardation is -10.8ms^-2.

Answer 2

Explanation:

It's 10.8 ms^-² hope it helps