Question

An electric vehicle starts from rest and accelerates at a rate of 3.0 m/s2 in a straight line until it reaches a speed of 25 m/s. The vehicle then slows at a constant rate of 1.0 m/s2 until it stops.

How much time elapses from start to stop?

Answer 1

First Phase
u=0
a=3 m/s^2
v=25 m/s
Second phase
u=25 m/s
a=-1 m/s^2
v=o

v=u+at
t1=(v-u)/a
t1=25/3 s

t2=-25/-1

therefore total time = t1+t2 = 25+(25/3)