Question

A small electric car has a constant acceleration of
1 m/s2
, a constant deceleration of 2 m/s2
and a top
speed of 72 km/hr. The amount of time it would take to
drive this car one kilometer starting from rest and
finishing at rest is

Answer 1

Answer:

Time it takes to reach 20m/s.

v=u+at =>t=20s

S=at2/2 =>S=400m

Time it takes to reach 0 again because it will start to decelerate

v=u+at=>20=2t=>t=10

Distance it will travel in this 10s=ut+at2/2 = 20x10-2x100/2

=100m

Total distance=500m time taken for it 30s

for distance 1000m time will be 60s since the same process will repeat again.