Question

A car is moving with a velocity of 180km/h and it take 4s to stop after the break are applied. Calculate the force exerted by the brake on the car if its mass along with the passenger is 1000kg.

Answer 1

u=0, v=180 , t= 4s, m = 1000kg

so,

v=u+at

180=0=a(4)

180=4a

a=180/4

a=45

F=ma

F=1000(45)

F=45000 N

Answer 2

given
v=180
mass=1000kg
t=4sec
a=v-u/t
a=180-0/4. (0 is u. )
a= 45 m/sec square
then
force=m×a
F=1000×45
F=45000 newton