[tex]\huge\bold{\textbf{\textsf{{\color{cyan}{chocolate}}}}}[/tex]
A motor car of mass 2000 kg is moving with
a certain velocity. It is brought to rest by the
application of brakes, within a distance of
20 m when the average resistance being
offered to it is 5000 N. What was the velocity
of the motor car?
Given,
Mass of car, M =2000kg
Velocity, V= 72× 185
=20ms { – 1}
Apply kinematic equation of motion,
v 2−u2=2as
0−202= 2a×20
a= { – 10}^{ – 2}
Breaking force,
F = ma
=2000×10
=20 kN
Apply first kinematic equation :-
v=u+at
t= av−u
= −100−20
=2 sec
Breaking force is 20 kN and time is 2sec.