Question

a car travelling at 36 km per hour speed up to 70 km/h in 5 seconds. what is its acceleration? if the same car stops in 20 seconds what is the retardation? ​Please tell fast. correct answer will get brainliest​

Answer 1

Answer:

retardation = 1 m/s2

Explanation:

u = 36 km/hr = 36 * (5/18) = 10 m/s

v = 72 km/hr = 20 m/s

by using first kinematic equation

we get :

v = u + at

20 = 10 + a(5)

thus,

a = 2 m/s²

Now the car stops in 20 seconds :

Using the same equation :

v = 0   &  u = 20 m/s  , t = 20 sec

a = ?

0 = 20 + a (20)

a = -1 m/s²

In 2nd case there is retardation of 1 m/s²

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