The driver of a car moving with a a velocity of `54 km h^(-1)` applies to decrease its velocity to `36 km h^(-1)`. If the retradation produced by the breaks is `2.0 m s^(-1)` , arrange the following steps in sequential order to calcualte the distan travelled by the car.
(a) Write down the required equation of motion as `v^(2)u^(2)=2as` where v,u,a and s are fianl velocity, initial velocity, retradtaion and desplaement,
(b) Write the down the given data and convert all the values into the same system of unit
(c) Get the value of 's' as `(v^(2)-u^(2))/(-2a)`
(d) Substitute the given values in the above equations

Options

A. A B D C
B. B A C D
C. A D B C
D. A B C D

Answer

C

Explanation

Given
`u=54 kmh^(-1)=54 xx (5)/(18) =15 ms^(-1)`
`V= 36 kmh^(-1) = 36 xx (5)/(18) =10 ms^(-1)`
`a= -2.0 ms^(-1)`
Using `v^(2)-u^(2) =2as (a)`
`s=(v^(2)-u^(2))/(-2a) (c )`
`s=(100-225)/(-4)(c )`
`s=125//4 =31.125m (d)`