Question

A bus is moving with the velocity 30km hr .On applying the brakes ,it comes to rest after travelling a distance 10m. Calculate the time taken by the bus.​

Answer 1

Explanation:

We know that..........

Here,30Km/hr=30×5/18=8.3 m/s(Initial velocity)

--Final velocity=0Km/hr, or ,0m/s(final velocity)

Distance traveled=10 metres

2as=v^2-u^2

Where,a=acceleration

s=distance traveled

v=Final velocity

u=Initial velocity

According to the question,

2×a×10=0^2-8.3^2

or,20a=0-8.3 ^2m/s

or,20a=(-8.3^2)

or,30a=(-68.9m/s)

or,a=(-68.9/30)

or,a=(-2.3m/s^2)

We also know that........

V=U+at

where,v=Final velocity

u=Initial velocity

t=Time

According to the question,

0m/s=8.3m/s+(-2.3m/s^2)(t)

or,(-8.3)=(-2.3)(t)

or,(-2.3)(t)=(-8.3)

or,t=(-8.3)/(-2.3)

or,t=3.6 seconds

Hope it helps...........