CIE IGCSE Physics Notes
Chapter 1 General Physics
1.1 Physical quantities and measurement techniques
• A ruler is used to measure length for distances between 1 mm and 1 meter.
• The SI unit for length is in meters.
• To measure the volume of a regular object you will need to know the formula and
several of its length. For e.g., to measure the volume of a solid box, you’ll need its
height x length x width.
• To measure the volume of an irregular object you put the object in a measuring
cylinder with water and measure the rise in water. The rise in water is the volume
of the object.
• Time is measured using clocks or watches.
• The SI unit for time is in seconds.
• You can increase the accuracy for measuring any object by taking an average value.
• For e.g., to measure the period of a pendulum, you can take the time it takes to
complete ten cycles instead of one and dividing the time by ten.
• A micrometre screw gauge is a tool used for measuring small widths, thickness, or
diameters
• It has a resolution of 0.01 mm
• A micrometre is made up of two scales:
1) main scale – this is on the sleeve (sometimes called the barrel)
2) the thimble scale – this is a rotating scale on the thimble
• The value measured from the micrometre is read where the thimble scale aligns
with the main scale.
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,CIE IGCSE Physics Notes
• A scalar quantity has magnitude only.
• Example of scalar quantities include distance, time, speed and mass.
• A vector quantity has both magnitude and direction.
• Example of vector quantities include distance, velocity, acceleration and force.
• The easiest way to tell if a quantity is scalar or vector is to know whether you can
put ‘’negative’’ sign in front of it.
• Example mass and time are both scalars because there is no “-“ seconds or “-“
kilograms.
• Velocity is a vector because you can have “-“ in front of the unit as you will see
later.
• Vectors can be added using triangle or parallelogram method.
Page | 2
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, CIE IGCSE Physics Notes
Triangular method
Parallelogram method
Page | 3
Senpaicorner.com
Chapter 1 General Physics
1.1 Physical quantities and measurement techniques
• A ruler is used to measure length for distances between 1 mm and 1 meter.
• The SI unit for length is in meters.
• To measure the volume of a regular object you will need to know the formula and
several of its length. For e.g., to measure the volume of a solid box, you’ll need its
height x length x width.
• To measure the volume of an irregular object you put the object in a measuring
cylinder with water and measure the rise in water. The rise in water is the volume
of the object.
• Time is measured using clocks or watches.
• The SI unit for time is in seconds.
• You can increase the accuracy for measuring any object by taking an average value.
• For e.g., to measure the period of a pendulum, you can take the time it takes to
complete ten cycles instead of one and dividing the time by ten.
• A micrometre screw gauge is a tool used for measuring small widths, thickness, or
diameters
• It has a resolution of 0.01 mm
• A micrometre is made up of two scales:
1) main scale – this is on the sleeve (sometimes called the barrel)
2) the thimble scale – this is a rotating scale on the thimble
• The value measured from the micrometre is read where the thimble scale aligns
with the main scale.
Page | 1
Senpaicorner.com
,CIE IGCSE Physics Notes
• A scalar quantity has magnitude only.
• Example of scalar quantities include distance, time, speed and mass.
• A vector quantity has both magnitude and direction.
• Example of vector quantities include distance, velocity, acceleration and force.
• The easiest way to tell if a quantity is scalar or vector is to know whether you can
put ‘’negative’’ sign in front of it.
• Example mass and time are both scalars because there is no “-“ seconds or “-“
kilograms.
• Velocity is a vector because you can have “-“ in front of the unit as you will see
later.
• Vectors can be added using triangle or parallelogram method.
Page | 2
Senpaicorner.com
, CIE IGCSE Physics Notes
Triangular method
Parallelogram method
Page | 3
Senpaicorner.com
