Question

A car is moving with a velocity of 12 m/s . On appling brakes, it comes to rest in 6sec. Calculate it's acceleration, distance covered in this time.

Answer 1

Information provided to us:

Initial velocity, u = 12 m / s
Final velocity, v = 0 ( Since, car finally comes to rest )
Time, t = 6 seconds

( I ) Acceleration, a = Change in velocity / Time
a = ( v - u ) / t
a = ( 0 - 12 ) / 6
a = ( - 12 ) / 6
a = - 2 m / s^2
Acceleration = - 2 m / s^2

( II ) Let the required distance be devoted by S.
S = ut + ( 1 / 2 ) * a * t^2
S = ( 12 * 6 ) + ( 1 / 2 ) * ( - 2 ) * ( 6 ^ 2 )
S = 72 + ( 36 / - 4 )
S = 72 + ( - 9 )
S = 72 - 9
S = 63 m

Hence,
Distance covered in this time = 63 m