Question

If a vehicle is running with a velocity of 72 km / hr. What should be the retardation of the vehicle to stop it 20 m ahead?

Answer 1

Answer:

-10 ms^2

Explanation:

as stopping distance=u^2/2a

u=72km/hr.=20m/s

20×20/2a=20m(given)

on solving we get

a=10ms^2

Answer 2

v=0. u=72*5/18=20
s=20m
from third equation of motion we have
v²=u²+2as
0=20²+2*a*20
0=400+40a
-4000=40a
a=-400/40
a=-10m/s²