Question

a car moving with a speed of 54km/hr is stopped by applying brakes in 10s.Find the retardation of the car​

Answer 1

Answer:

1.5 m/s^2

Explanation:

According to the given question,

u = initial velocity = 54 km/hr

= 54× 1000/3600 = 15 m/s

v = final velocity = 0 m/s

t = time = 10 sec

-a = deceleration = ?

and we are asked to find the deceleration or retardation of the moving car.

We know,

• v = u+at

• 0 = 15 + a× 10

• -15 = 10a

• a = -15/10

• a = -3/2

• a = - 1.5 m/s^2

Here negative sign indicates the deceleration of the car.

And it means that acceleration is 1.5 m/s^2 opposite to the direction of motion of car which is simply retardation.

Answer 2

Answer:

Explanation:

v=0 as the car is stopped.

v means final velocity.

u = 54km/hr or 15 m/ sec .

u means initial velocity.

time = t = 10 seconds.

a = v- u÷ t

0-15÷10

=-15÷ 10

=-1.5m/ sec square