A vehicle moving with velocity 2 m/s can be stopped over a distance of 2 m keeping the retarding force constant, if kinetic energy is doubled, what is the distance covered before it comes to rest?
Given that,
Mass = m
u1 = 2 m/s
s = 2 m
and v = 0
Using equation,
v2 – u2 = 2as
=> 0 – 22 = 2×a×2
=> a = -1 ms-2
KE of the body = ½ m(2)2
= 2m
Now KE if doubled then KE = 4m
Let velocity of the body become u2
½ mu2 2 = 4m
=> u2 = 2√2
Let s’ be the distance at which it will stop
v2 – u2 = 2as’
=> 02 – (2√2)2 = 2×(-1)×s’
=> s = 4 m