Applications of integration (Chapter 16) 445
Example 7 Self Tutor
The velocity-time graph for a train journey is
illustrated in the graph alongside. Find the total
distance travelled by the train.
Total distance travelled
=total area under the graph
=area A+area B+area C+area D+area E
=^12 (0:1)50 + (0:2)50 +
¡50+30
2
¢
(0:1) + (0:1)30 +^12 (0:1)30
=2:5+10+4+3+1: 5
=21km
EXERCISE 16C.1
1 A runner has the velocity-time graph shown. Find the
total distance travelled by the runner.
2 A car travels along a straight road with the velocity-time
function illustrated.
a What is the significance of the graph:
i above thet-axis
ii below thet-axis?
b Find the totaldistancetravelled by the car.
c Find the final displacementof the car from its
starting point.
3 A cyclist rides off from rest, accelerating at a constant rate for
3 minutes until she reaches 40 km h¡^1. She then maintains a
constant speed for 4 minutes until reaching a hill. She slows
down at a constant rate over one minute to 30 km h¡^1 , then
continues at this rate for 10 minutes. At the top of the hill
she reduces her speed uniformly and is stationary 2 minutes
later.
a Draw a graph to show the cyclist’s motion.
b How far has the cyclist travelled?
01. 02. 03. 04.
30
05. 06.
60
O t( )h
v(km h-1)
01. 02. 01. 01. 01.
A BCDE
50 50 30 30
5 10 15 20
2
4
6
8
velocity m s()¡-1
O time s()
10
-20
20
40
60
O
t( )h
velocity km h()-1
0101 .. 0202 .. 0303 .. 0404 .. 0505 .. 0606 .. 0707 ..
4037 Cambridge
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Y:\HAESE\CAM4037\CamAdd_16\445CamAdd_16.cdr Monday, 7 April 2014 4:18:04 PM BRIAN