Question

A car is moving in a straight line with a speed of 18 km/hr . It stopped in 5 sec by applying the brakes. Find the speed of the car 2 seconds after applying the brakes. Pls solve with working.

Answer 1

Answer:speed of car=18km/h=18×5/18=5m/s

Time=5sec

V=U+AT

5=0+a×5

Acceleration=1m/s^2

As the car applies brakes(therefore it is retardation)

Now,u=5m/s, acceleration=-2m/s^2

V=U+AT

=5+(-1×2)

=3m/s

Explanation:

Answer 2

Car speed is 3 m/s.

Given,

Initial velocity (u) = 18km/hr. or 5 m/s.

Final velocity (v) = 0m/s.

Time is taken by the car to stop = 5sec.

To Find,

The speed of the car is 2seconds after applying the break.

Solution,

The equation of the motion,

v = u + at.

and, here

a = -1m/$s^{2}$

0 = 5 + a(5).

The car speed 2second after applying the break,

v = u + at.

v = 5 -1 (2)

v = 5 - 2

v = 3m/s.

Hence 3 m/s is the speed of the car 2 seconds after applying the break.

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