Question

A car moving along a straight highway with speed of 54 km/h is brought to stop within a distance of 50m. How long does the car take to stop?

Answer 1

Answer: u = 54 km/h =54000/3600 = 540 /36 = 15m/s

using

v^2 - u^2= 2as        we have

0 - 225 = 2 a (50)

-225 = 100a

a= -2.25

now, v= u+at

0 = 15 + (-2.25)t

t= 15/2.25 = 6.67s