Question

A car is travelling with the velocity of 72 km/hour. If brakes applied produce uniform retardation of 10m/s². Calculate the time taken by it to stop.

Answer 1

Hey!

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Initial velocity (u) = 72 km/h = 20 m/s
Final velocity (v) = 0
Acceleration (a) = - 10 m/s^2
Time taken to stop (t) = ?

We know,

v - u = at
0 - 20 = -10 × t
-20 = -10t
-20/-10 = t

t = 2 s

Time taken to stop = 2 seconds.

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Hope it helps...!!!

Answer 2

Hi there !!
Here's your answer

Given,
Initial velocity of the car (u) = 72km/hr = 20m/s
Final Velocity (v) = 0m/s [ the car will come to rest after the given time is completed ]
Acceleration (negative) = -10m/s²
Let the time taken be t

To calculate the time ,
we will use the 1st equation of motion

that is

v = u + at
0 = 20 + (-10)(t)
0 = 20 - 10t
10t = 20
t = 20/10
t = 2

Thus,
the time taken to stop will be 2 seconds

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hope it helps :D