## 1.2.2 Derived Quantities

Derived Quantities

A derived quantity is a Physics quantity that is not a base quantity. It is the quantities which derived from the base quantities through multiplying and/or dividing them.
Example

(Speed is derived from dividing distance by time.)

Derived Unit
The derived unit is a combination of base units through multiplying and/or dividing them.
Example 1
Find the derived unit of density.
Unit Conversion
Area and Volume
Example 2
Convert the unit of length, area and volume below to the units given.
a) 7.2 m = ____________cm
b) 0.32 m2 = ____________cm2c) 0.0012 m3 = ____________cm3d) 5.6 cm = ____________m
e) 350 cm2 = ____________m2f) 45000 cm3 = ____________m3Answer
a) 7.2 m = 7.2 x 102 cm
b) 0.32 m2 = 0.32 x 104 cm2 = 3.2 x 103 cm2
c) 0.0012 m3 = 0.0012 x 106 cm3 = 1.2 x 103 cm3
d) 5.6 cm = 5.6 x 10-2 m
e) 350 cm2 = 350 x 10-4 m2 = 3.5 x 10-2 m2
f) 45000 cm3 = 45000 x 10-6 m3 = 4.5 x 10-2 m3

Speed
Example 3
Complete the following unit conversion
a) 12 kmh
-1 = __________ ms-1
b) 12 ms
-1 = __________ kmh-1

a) $\begin{array}{l} 12km{h^{ - 1}}\\ = \frac{{12km}}{{1h}}\\ = \frac{{12000m}}{{60 \times 60s}}\\ = 3.33m{s^{ - 1}} \end{array}$

b)
$\begin{array}{l} 12m{s^{ - 1}}\\ = \frac{{12m}}{{1s}}\\ = \frac{{\frac{{12}}{{1000}}km}}{{\frac{1}{{3600}}h}}\\ = 43.2km{h^{ - 1}} \end{array}$

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This comment has been removed by the author.
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This comment has been removed by the author.
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