a derived quantity is a physics quantity that is not a base quantity
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8/7/2019 A Derived Quantity is a Physics Quantity That is Not a Base Quantity
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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
(S peed 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.
Answer
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Unit Conversion
Area and Volume
Example 2
C onvert the unit of length, area and volume below to the units given.
a) 7.2 m = ____________cm
b) 0.32 m2
= ____________cm2
c) 0.0012 m3
= ____________cm3
d) 5.6 cm = ____________m
e) 350 cm2 = ____________m2
f) 45000 cm3
= ____________m3
Answer
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
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f) 45000 cm3
= 45000 x 10-6
m3
= 4.5 x 10-2
m3
Speed
Example 3
C omplete the following unit conversion
a) 12 kmh-1
= __________ ms-1
b) 12 ms-1 = __________ kmh-1
Answer
a){\rm{ 12kmh}}^{{\rm{ - 1}}} {\rm{ = }}{{{\rm{12km}}} \over {{\rm{1h}}}}{\rm{ =
}}{{{\rm{12,000m}}} \over {{\rm{60 \times 60s}}}}{\rm{ = }}{{{\rm{10}}} \over
{\rm{3}}}{\rm{ms}}^{{\rm{ - 1}}}
b){\rm{ 12ms}}^{{\rm{ - 1}}} {\rm{ = }}{{{\rm{12m}}} \over {{\rm{1s}}}}{\rm{ = }}{{{{{\rm{12}}}
\over {{\rm{1000}}}}{\rm{km}}} \over {{{\rm{1}} \over {{\rm{60 \times 60}}}}{\rm{h}}}}{\rm{ =
43}}{\rm{.2kmh}}^{{\rm{ - 1}}}
Prefixes are the preceding factor used to represent very small and very large physical
quantities in SI units.
Conversion of prefixes
Prefixes to Normal Number Example 1
The frequency of the radio wave is 350M Hz. What is the frequency of the radio wave
in Hz?
Answ er
Mega (M) = 1,000,000 or 10 6
Therefore,
350MHz = 250 x 106Hz
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Example 1
ategorize each quantity elo as eing either a vector or a scalar.
Speed, velocity, acceleration, distance, displacement, energy, electrical charge,
density, volume, length, momentum, time, temperature, force, mass, po er, ork,
impulse.
Answer:
Scalar Quantities:
y speed
y distance
y energy
y electrical charge
y density
y volume
y length
y time
y temperature
y mass
y po er
y ork
Vector Quantities
y velocity
y acceleration
y displacement
y momentum
y force
y impulse