Question

A car starts from rest and moves along the x-axis with constant acceleration 5 m/s2 for

8 seconds. If it then continues with constant velocity, what distance will the car cover in

12 seconds since it started from the rest?

Answer 1

v=u+at
=5×8
=40m/s

distance travelled in 8 sec
s=ut+1/2at^2
s=1/2×5×64
s=160m

distance travelled in 4 sec
40×4=160m
total distance = 160+160=320m

Answer 2

u=0

a=5ms

t=8 sec

using 2nd equation of motion=s=ut+1/2at

20×8+1/2×5×640+160=160

It's is given that the car moving with constant velocity

using first equation of motion =v=u+atv

=0+5×8v=40

the distance travelled by the car (12-8)=4sec

40×4=160

the distance covered by the car in 12 sec is 160+160=320