Question

A car is moving in a staright road with a speed of 35m/s and is brought to rest within a distance of 200m what is the retardation of the car
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Answer 1

Given :

A car with initial velocity (u) = 35 m/s.

Distance travelled before coming to rest (s) = 200m.

To Find:

Retardation of the car .

Solution :

Initial velocity (u) = 35 m/s.

Final velocity (v) = 0 (Since the car is coming to rest so it has not velocity at the end)

Distance = 200m.

Acceleration =  ?.

1. Unit conversion is not required because all the quantities are mentioned in S.I units.

From the equation of kinematics we have :

$v^{2}$ - $u^{2}$ = 2*a*s (Third equation of kinematics)

On substituting we get,

-( $35^{2}$)= 2*a*200,

=> a= (-35*35)/(2*200)

=> a= -3.062 m/$s^{2}$.

NOTE: (The negative sign of the acceleration implies that the car is undergoing deceleration . Since all the units are given in S.I , Therefore the final answer is also mentioned in S.I units )