Question

A car starts with an acceleration of 2m/s2 and it accelerates for 5 seconds and for another 5 seconds it runs with constant velocity and then deaccelerates with 2m/s and finally comes into rest. Find 1.Total distance travelled 2.Average velocity

Answer 1

u = 0
a = 2m/s²
t = 5s
S = ut+½at²
= 25m
v =u+at
=0+2*5
= 10m/s

Now, speed = 10m/s
Time = 5s
Therefore, distance= s*t
=10*5 = 50m

Again, acceleration=-2m/s²
u =10m/s
v = 0
Therefore,time = v-u/a = 0-10/-2 = 5 s
and, s= v²-u²/2a
= -100/2*(-2)
= 25m

1. Total distance =25+50+25 =100m
2. Avg. Velocity = Total distance/total time
= 100/5+5+5
= 100/15
= 6.66m/s