Question

A bus was moving with a speed of 54 km/h .on applying brakes ,it stopped in 8second. calculate the acceleration and the distance travelled before stopping

Answer 1

Hii there!!!

Initial velocity(u)= 54×1000/60×60
= 15m/s
Final velocity(v)= 0m/s
Time(t)= 8sec
a= v-u/t
a= 0-15/8
a= -1.875
( It is deceleration as the car is stopping, therfore it is negative. )

2as= v^2- u^2
2×-15/8×s= (0)^2 - (15)^2
-15/4×s= -225
s= -225*-4/15
s= 60m ANS

Hope it helps....

Answer 2

u = 54 km /h = 15 m/s
t= 8s
v=0 m/s
We have to find a.
v= u + at
0=15 + 8a
-15= 8a
a = -15/8 m/s²
v²= u²+2 as
0= 225 + 2 x -15/8 x s
s = 60 m