Page 6 - 1202 Question Bank Physics Form 4

1
Chapter Measurement

NOTES

1.1 Physical Quantities
S.I. unit Symbol
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1. Physics is the study of space, time, matter and
energy as well as phenomena happening around us. metre m
2. Measurement plays an important role in investigating kilogram kg
natural phenomena and inventing modern equipment
to solve problems in our lives. second s

3. Measurement is a method to determine the value
kelvin K
of a physical quantity. The results of accurate
measurements enable us to make right decisions.
ampere A
4. Physical quantities are quantities that can be
measured, consists of a numerical magnitude and candela cd
a unit.
Magnitude mole mol
Physical
quantity Length = 10 m Unit 7. Derived quantities are physical quantities that are
derived from the mathematical combinations of base
5. All measurement requires a system of units. We quantities through multiplication or division or both.
always express the result of a measurement as a
number (numerical magnitude) multiplied by a unit. 8. Scalar quantity is a physical quantity that can be
The metric system of units considered superior to expressed in terms of its magnitude only.
most other systems of units.
9. Vector quantity is a physical quantity that must be
Example: Length = 10 m means 10 multiplied by
expressed in both magnitude and direction.
the length of one metre
Examples of scalars
6. Base quantities are physical quantities that cannot
be derived from other physical quantities. These Distance Density
base quantities cannot be defined in terms of more
fundamental quantities. Speed Temperature

Base quantity Symbol
Time Energy
Length l
Mass Power
Mass m
Examples of vectors
Time t
Displacement Momentum
Thermodynamic temperature T
Velocity Impulse
Electric current I
Acceleration Weight
Luminous intensity I
v
Force Field strength
Amount of substance n

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