A bus is moving with a velocity of 72km/hr. on seeing the red signal of traffic at 27m ahead on the road, the driver applied brakes and the bus stopped at a distance of 25m. calculate the time taken by the car to come at rest plz help me

Since there is negative acceleration, a= -2m/s^2 . As brakes are applied, it's final velocity (v) becomes 0m/s and it's initial velocity (u) will be 20m/s .

So to find the time for which my Nano will stop we make use of one of the kinematical equation.

v=u+at  

0=20+(−2)t  

−20=−2t  

t=10seconds.  

So my Nano will take 10 seconds to stop.

Now to calculate the distance for which my Nano will stop is given by;

v2=u2+2ax  

(0)2=(20)2+2(−2)x  

0=400−4x  

−400=−4x  

x=100metres.  

So after applying brakes my Nano will stop after a distance of 100m.

Explanation: