Question

A vehicle moving with a speed of 36km/h applies brake and stops after covering 10 m distance. On moving at a speed of 72km/h and applying brakes it stops after covering 30 m distance. Assuming same reaction time and same acceleration in each case, the distance covered before stopping when brakes are applied on the vehicle when it is moving at 54km/h is what?

Answer 1

Answer:

u=36km/h=10m/s

t=5s

v=0m/s

1). a=(v-u)/t

a=(0-10)/5

a=-10/5=-2m/s²

so,retardation is 2m/s².

2). v²=u²+2aS

0²=10²+2*(-2)*S

0=100-4*S

S=-100/-4=25m Ans.