n normal driving, Kerry accelerates at 2.0 m sï€2 and
slows gently with an acceleration of ï€ 1.5 m sï€2.
(a) Find the distance travelled and the time taken when Kerry accelerates from rest
to 60 kph, and compare it with the distance travelled and time taken if the
maximum speed is 50 kph.
(b) Find the distance travelled and the time taken in coming to rest from a speed of
60 kph, and compare it with the distance and time required to stop from a
speed of 50 kph.
(c) Suppose Kerry’s journey to work can be approximated by 8 segments, each of
which has a length of 500 m on residential streets and involves accelerating
from rest, travelling at the speed limit, then coming to rest again. Estimate the
increase in travel time when the speed limit was reduced from 60 to 50 kph.