Page 78 - MATHEMATICS COURSE FOR SECONDARY SCHOOLS BOOK 2

ExXeErcRiseC1I1SPE 4.1
1 Calculate the circumference of each of
2.5 cm Room appro
7 A pipe has an inner diameter of 2.5 cm and an outer diameter of 3 cm.
(a) What is the circumference of:
(i) its inner surface (ii) its outer surface if 􏰀 = 3.14?.
with 8 cm.
t to imming
.
ect to
2
–, the
22 these circles, using 􏰀 = ––.
to a sp rises o as the
(a) (b)
14 cm
7 (c)
(d)
5.6 cm
35 cm
3.5 cm
(b) What distance does a point on: Meas
OOOO
2 The circumference of a circular lake is 157 m. Taking 􏰀 as 3.14, find:
(a) its diameter (b) its radius.
3 The diameter of the top of a milk can is
15 cm. Calculate the circumference of the top of the milk can. Use 􏰀 = 3.14.
4 The radius of a car wheel is 35 cm. How far
does the car go in
one turn of the
wheels? Use 􏰀 = 3.14.
5 The distance around a circular racing
track is 440 m. What is the length of:
(a) its radius (b) its diameter?
(i) its inner surface (ii) its outer surface cover if the pipe rotates 25 times?
AREA OF A CIRCLE
Temperature
If you say that on a sunny day the room is hot, on a rainy day it is cold or on a windy day it is cool, you are talking about
temperature. You use
this measurable attribute when you say that fire is very hot, ice is very cold
or a pet cat or rabbit is warm.
Words such as hot, cold, cool and warm are all associated with temperature.
Temperature is a measure of how hot (or cool) an object is.
Temperature scales
Fixed values are assigned to real physical conditions that occur at set temperatures, for example, the freezing point and the boiling point of water. Temperature scales are calibrated from these fixed points. In daily life you use the Celsius and Fahrenheit scales. Scientists may use the absolute scale.
The in used t the th
The di therm
7
= 􏰀d = 72–, the
= 2􏰀r = 3.14,
imming d.p.).
Activi
1 (a)
(b)
Use 􏰀 = 2–2–. 7
6 The equator is an imaginary line round the centre of
the Earth. The radius of
the equator is 6370 km.
(a) What is the circumference of the Earth at the equator?
6.370 km
.14, the pool is
.)
imming
(b) What is the diameter of the Earth?
(c) What distance does a point on the equator travel when the Earth spins on its axis seven times?
Scale
Celsius Fahrenheit Absolute
Unit
degree (C) degree (F) Kelvin
Melting point of pure w
°C 0°C °F 32°F K 273K
Take 􏰀 = ––. 7
22
72
c w s
r
2 –
C
2 –
C
t x
e r
n
u
s o
e
a o
3
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