Area
cm≤, m≤
Volume
cm≥, m≥, litre (l), millilitre (ml)
Density
kg/cm≥, g/cm≥
Force
Newton (N)
Speed/ Velocity
m/s, km/h
Acceleration
m/s≤
Mass
kilogram (kg), gram (g)
Time
second (s)
Length
metre (m), kilometre (km), centimetre
(cm)
Temperature
degrees Celsius (C∞)
current
ampere or amp (A)
1 km
1000m
100,000cm
1 tonne
1000kg
1000,000g
1 hour
60 minutes
3600 seconds
1L
1000 ml
1000cm≥
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Speed
o The rate of change in distance
o Is a scalar quantity
Velocity
o The rate of change in displacement
o Is a vector quantity
Type
d-t
v-t
Gradient
Velocity
Acceleration
Value
Displacement
Velocity
Area
a-t
Acceleration
Displacement
How to measure gradient:
Gradient = Rise ˜ Run
Average Speed = Total Distance ˜ Total Time
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An object will have acceleration if:
The magnitude of velocity changes
The direction of motion changes
When describing velocity, a direction must be given.
Some objects only have two directions, e.g. backward, forward
When this happens, you can name the two directions „positive‟ and „negative‟ so that calculations are
simpler
Change in Velocity = New velocity measurement - Previous velocity measurement
Change in Velocity = V - U
Acceleration = Change in Velocity ˜ Time
Acceleration = (V - U) ˜ T
Example:
A person drives at a velocity of 40 m/s North
He accelerates, increasing his velocity to 50 m/s North in 10 seconds
o V = 5 m/s North
o U = 4 m/s North
o Change in Velocity = 5 m/s - 4 m/s
= 1 m/s North
o T = 10 seconds
o Acceleration = 1 m/s North ˜ 10 s
= 0.1 m/s≤
Example:
A ball drops and hits the ground at 5 m/s and bounces back at 3 m/s in 1 seconds
o Up = Positive
o Down = Negative
 V = 3 m/s
 U = -5 m/s
 Change in Velocity = 3 m/s - (-5 m/s)
= 3 m/s + 5 m/s
o = 8 m/s Up
 T = 1 seconds
 Acceleration = 8 m/s Up ˜ 1 s
8 m/s≤ Up
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Forces
A force is a push or a pull
A force is an action that can make another object change shape or change its velocity A
force is an action that can make another object accelerate
Are divided into two categories; Contact and Non-Contact
E.g. gravitational, electrostatic, twisting etc.
 Friction is a contact force involving two bodies opposing each others motion
o E.g. the friction of the tyres of a car on the road cause the car to move slower
 Gravitational force acts on falling objects. They reach a terminal velocity when the up
thrust is equivalent to the gravitational force.
o When objects fall, the force of gravity acts upon them o
As gravity increases, air pressure increases
o When air pressure is equal to gravity, the object travels in a straight line o
This is called terminal velocity
o This is the constant speed at which an object falls to earth
When force acts on an object, it causes the object to change the value of velocity and the direction of
movement.
EXAMPLES OF FORCE:
Weight:
The gravitational force from the earth It
acts vertically down
Normal Force:
Acts 90∞ to the surface
Is equal to weight
Friction Force:
Has the direction opposite to the direction of movement
Acts between two surfaces
Tension Force:
Acts against the deformation of a body
It takes place in a string or a rope Drag
Force:
Acts in the case of air resistance
It has the direction against motion
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Mass:
Is the amount of resistance an object has towards movement Is
defined as the amount of substance in an object
Force = mass ◊ acceleration
F=mxa
Weight = mass ◊ gravity
W=mxg
Gravity (10N/KG)
When force acts on an object, it causes the object to change the value of velocity and the direction of
movement.
EXAMPLES OF FORCE:
Weight:
The gravitational force from the earth It
acts vertically down
Normal Force:
Acts 90∞ to the surface
Is equal to weight
Friction Force:
Has the direction opposite to the direction of movement
Acts between two surfaces
Tension Force:
Acts against the deformation of a body
It takes place in a string or a rope Drag
Force:
Acts in the case of air resistance
It has the direction against motion
Stopping Distance
Stopping Distance = Thinking Distance + Breaking Distance
Page 7 of 30
Factors affecting thinking distance:
Thinking distance is the distance a car travels when the driver is reaction to a situation
o
o
o
o
o
Alcohol
Other drugs and some medicines
Distraction (e.g. mobile phones)
Speed
Tiredness
Factors affecting braking distance
Breaking distance is the distance a car travels after the breaks have been applied
o
o
o
o
Weather
Condition of the road
Speed
Condition of tyres and breaks
Momentum = Force ◊ Perpendicular Distance from the Pivot
Force x Distance
=
Force x Distance
40 Newtons x 6 Metres
=
80 Newtons x 3 Metres
Moment
Is a turning force
When a force causes rotation about a pivot
When System is in Equilibrium
Clockwise Moment = Anticlockwise Moment
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Centre of Mass
o Centre of mass is a single point in a body where all the mass appears to be
Centre of Gravity
o Centre of gravity is a single point in a body where all the force of gravity appears to
act
Initial linear region of force-extension graph is associated with Hooke‟s
law
Extension is proportional to the force providing the elastic limit is not
exceeded
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Page 11 of 30
Mass
Energy
Distance
Speed
Acceleration
Force
Time
Power
Kilogram (kg)
Joule (J)
Metre (m)
Metre/second (m/s)
Metre/second2 (m/s2)
Newton (N)
Second (s)
Watts (W)
Energy transfers in many ways such as:
Thermal (Heat)
Light
Electrical
Sound
Kinetic
Chemical
Nuclear
Potential (Kinetic, Elastic and Gravitational)
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Energy is conserved
 Energy cannot be created or destroyed, only transferred.
Efficiency = Useful Energy Output ˜ Total Energy Input
Efficiency = Work ˜ Total Energy Input
Sankey Diagram
Energy transfer can take place in many ways such as:
Convection
o Heat transfers in liquids and gases
o Fluids (liquid or gas) become less dense when heated
 The lower density makes the warm fluid rise and cold fluid move down
Conduction
o Energy transfers through solids
o Conduction occurs when there is contact
o In metals, conduction is due to free electrons
o Bad conductors are insulators
Radiation (Infra-Red Radiation)
o It is the way energy moves through space (vacuum)
o It travels as electromagnetic waves with a speed of 300,000,000 ms-1. [3x108 ms-1]
o It needs a medium to travel through
Energy Loss at Home - Insulation
Windows
o Needs double glazing
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Roof
o Fibre wool insulation
Gaps
o Draught excluders
Walls
o Cavity wall insulation
Marble/Stone floors
o Carpets
Work Done = Force x Distance Moved
W=Fxd
Work done is always equal to energy transferred measured in Joules (J)
Work Done = Energy Transferred
Energy Transferred = Force x Distance Moved
Gravitational Potential Energy = Mass x Gravity x Height
GPE = m x g x h
Kinetic Energy = Ω x mass x speed2
KE = Ω x m x v2
Power is the rate of transfer of energy or the rate of doing work measured in Watts (W)
Power = Work Done ˜ Time Taken
P=W˜t
Energy transfers involved in generating electricity are:
Renewable sources of energy:
o Wind
o Water
o Geothermal Resources
o Solar Heating Systems
o Solar Cells
Non-Renewable sources of energy:
o Fossil Fuels
o Nuclear Power
Page 14 of 30
Celsius (0C)
Kelvin (K)
Newton (N)
Pascal (Pa)
Newton/ metre≤ (N/m≤)
Kilograms/metre≥ (kg/m≥)
Grams/millilitre (g/ml)
Grams/centimetre≥ (g/cm≥)
Metre (m)
Metre≤ (m≤)
Joule (J)
Kilogram (Kg)
Metre/second (m/s)
Metre/second≤ (m/s≤)
Temperature
Force
Pressure
Density
Distance
Area
Energy
Mass
Speed
Acceleration
Density
Measure of mass per unit volume for any substance 
KG / M≥
Density = Mass ˜ Volume
D=m˜V
Pressure
Measure of force per unit area 
N / M≤
 Pa
Pressure = Force ˜ Area
P=F˜a
Pressure in liquids and gases
Pressure = Density x Height x Gravity
P=Dxhxg
Density of some substances:
 Pure Water
o 1000 kg/m≥
 Air
o 1.2 kg/m≥
Atmospheric
Pressure
100 000 N/m≤
Page 15 of 30
Brownian Movement
Brown observed pollen grains moving around randomly in water
He concluded that water particles were colliding with pollen grains and causing random
motion
Brownian movement also supported the idea that gas particles are also moving in random
motion in all directions with a range of speeds
Assumptions of Kinetic Theory of Gases:
Particles are points
Particles are more in straight lines between collisions
Collisions are elastic (bounce back with same speed)
Many particles, lots of space
Continuous random motion
Boyles Law
For a fixed mass of gas, the pressure is inversely proportional to the volume if the
temperature remains constant
Pressure is inversely
proportional to volume
Pressure is proportional
to the inverse of volume
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Charles Law
For a fixed mass of gas, the volume is proportional to the absolute temperature if the
pressure remains constant
Pressure Law
For a fixed amount of gas, the pressure is proportional to the absolute temperature if the
volume remains constant
∞ Celsius
-273
0
100
Kelvin
0
273
373
 As temperature increases, the speed of molecules increases
Pressure 1 x Volume 1 = Pressure 2 x Volume 2
P1 x V 1 = P2 x V 2
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Frequency
Force
Speed
Time
Degree (0)
Hertz (Hz)
Metre (m)
Metre/second (m/s)
Second (s)
Transverse Waves
A transverse wave is one that vibrates, or oscillates, at right angles to the direction in which the
energy or wave is moving
Longitudinal Wave
A longitudinal wave is one in which the vibrations, or oscillations, are along the direction in
which the energy or wave is moving
Transverse Waves
Longitudinal Waves
Waves Inside Fluids
Surface Waves
Shock Waves
Electromagnetic Waves
Seismic Waves (Underground Waves)
Seismic Waves (Surface Waves)
Sound Waves
Light Waves
Page 18 of 30
Amplitude
The maximum movement of particles from their resting position caused by a wave
Unit: A
Frequency
The number of waves produced each second by a source, or the number passing a
particular point each second
Unit: Hz (Hertz, 1 ˜ s )
Wavelength
The distance between a particular point on a wave and the same point on the next wave
(for example, from crest to crest)
Unit: λ (in metres, m )
Period
The time it takes for a source to produce one wave
Unit: T (in seconds, s )
Waves are a means of transferring energy from place to place, without the transfer of matter
Wave Speed = Frequency ◊ Wavelength
v=f◊λ
Wave speed is measured in metres per second ( m ˜ s )
Frequency = 1 ˜ Time Period
f=1˜t
Law of reflection states that the angle of incidence is equal to the angle of reflection when light
strikes a plane mirror
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Luminous Objects
Objects that emit their own light
E.g.
o Sun
o Stars
o Fire
o Light bulbs
Non-Luminous Objects
Objects that that do not emit light
We can see them because of the light they reflect
Virtual Images
Images though which rats of light do not actually pass
Real Images
Images created with rays of light actually passing through them
Properties of an image in a plane mirror:
The image is as far behind the mirror as the object is in front Te
image is the same size as the object
The image is virtual - that is, it cannot be produced on a screen
The image is lateral invested - that is, the left side and right side of the image appear to be
interchanged
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Medium
A material through which light can travel
Speed of light:
In a vacuum and in air
o 300 000 000 m/s
In water:
o 200 000 000 m/s
Refraction
Is a property of waves changing speed (and direction) when passing a boundary
Snell‟s Law:
States that the ratio of sine angle incidence and sine angle refraction is a constant for a boundary
between two materials
n = Sin i ˜ Sin r
Refractive Index = Sin (Angle of Incidence) ˜ Sin (Angle of Refraction)
Total Internal Reflection:
Is an optical phenomenon where light (waves) refract and reflect back at a boundary
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Critical Angle:
Is the angle where light reflects back and refraction is along the boundary
Sin C = 1 ˜ n
Sin (Critical Angle) = 1 ˜ Refractive Index
Reflectors
Use tiny prisms in their construction
The optical material is plastic - lighter and less fragile then a mirror
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Speed of sound depends on the air (gas) temperature (since particles may be closer when
gas is cooler)
Average speed of sound in air is approximately 340 m/s
Average speed of sound in seawater is approximately 1500 m/s
Average speed of sound in a solid is approximately 5000 m/s
Audible Range for:
Humans:
o 20 Hz - 20 000 Hz
Dogs, dolphins and bats:
o Over 20 000 Hz
Infrasounds
Sounds that cannot be heard by human beings as they are produced by objects that vibrate at
frequencies lower than 20 Hz
Ultrasounds
Sounds that cannot be heard by human beings as they are produced by objects that vibrate at
frequencies higher than 20 000 Hz
Loudness
Is the measure of the power of a sound
o A wave with a big amplitude is loud
o A wave with a small amplitude is soft
Echo
A reflected sound
Echo Sounding
When ships use echoes to discover the depth of the water beneath them
Pitch
The frequency of sound waves
Measuring the Speed of Sound:
Using echoes
o (2 x distance between presentation of sound and large blank wall) ˜ time between
presentation of sound and presentation of echo
Using an oscilloscope
Page 23 of 30
Current (I)
Charge (Q or q)
Energy (E)
Resistance (R)
Time (t)
Voltage (V)
Power (P)
Ampere (A)
Coulomb (C)
Joule (J)
OHM (Ω)
Second (s)
Volt (V)
Watt (W)
Live Wire
Provides the path along which the electrical energy from the power station travels Is
alternately positive and negative causing alternating current (ac) to flow along it
Brown in colour
Neutral Wire
Completes the circuit
Blue in colour
Earth Wire
Usually has not current flowing through it
Is there for protection if an appliance develops a fault
Green and yellow in colour
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Hazards of Electricity:
Frayed cables
Long cables
Damaged plugs
Water around sockets
Pushing metal objects into sockets
Safety Devices:
Fuses
o Usually in the form of a cylinder or cartridge
o Contains a thin piece of wire made from a metal that has a low melting point
 If too large a current flows in the circuit, the fuse wire becomes very hot and
melts
 The fuse „blows‟, shutting the circuit off
 Prevents shock and reduces possibility of an electric fire
o The correct fuse to use is one that allows the correct current to flow but blows if the
current is a little larger
Trip Switches or Circuit Breakers
o If too large a current flows in a circuit, a switch opens making the circuit
incomplete
o Once the fault in the circuit is corrected, the switch is reset, usually by pressing a
reset button
 Does not need to be replaced
Earth Wires
o Provides a low-resistance path for the current if and when the live wire becomes
frayed or breaks and comes into contact with the metal casing
o Prevents severe electric shock as electricity passes through a person to the earth
Double Insulation
o Is when all electrical parts of an appliance are insulated with non-conductors so
that they cannot be touched by the users
o Appliances that have this do not require an earth wire
Heating elements are designed to have a high resistance
As the current passes through the element, energy is transferred and the element heats up
E.g.
o Toaster
o Kettle
o Dishwasher
o Cooker
Resistance prevents the flow of current, and causes an increase in temperature by doing so
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Power = Current x Voltage
P=IxV
Energy = Power x Time
E=Pxt
Energy = Current x Voltage x Time
E=IxVxt
Alternating Current (ac)
The flow of electricity is constantly changing direction
Direct Current (dc)
The flow of electricity is always in the same direction
Electric Current
A flow of charge
Good Conductor of Electricity
A material through which electrons flow easily
o Electrons carry charges
Insulators
A bad conductor of electricity
Used to prevent the flow of charge
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Current is the rate of flow of charge
Charge = Current x Time
Q=Ixt
Ammeter
Used to measure the size of the current flowing in a circuit
Voltmeter
Used to measure voltage
Battery
Consists of several cells connected together
Provides current flowing in one direction (dc)
Light Emitting Diode (LED)
Fitted to many appliances to show when the appliance is switched on or on standby
Glows when current is flowing through it
Page 27 of 30
Series Circuit
No branches or junctions
One switch can turn all the components on and off together
If one bulb (or other component) breaks, it causes a gap in the circuit and all of the other
bulbs will go off
The voltage supplied by the cell or mains supply is “shared” between all the components
o The more bulbs added, the dimmer they all become
o The larger the resistance of the component, the bigger its „share‟ of the voltage
Parallel Circuit
Have branches or junctions
Switches can be placed in different parts of the circuit to switch each bulb on and off
individually, or all together
If one bulb (or other component) breaks, only the bulbs on the same branch of the circuit
will be affected
Each branch of the circuit receives the same voltage
o Even if more bulbs are added, they all stay bright
Page 28 of 30
Resistance
Is a measure of energy dissipated by charge when unit current flows All
components offer some resistance to the flow of charge
o Some circuits allow charges to pass through them very easily losing very little
energy
 i.e. the components have a very low resistance
o Some circuits do not allow charges to pass through them as easily and hence lose a
significant amount of energy
 i.e. the components have a very high resistance
The energy is converted into other forms, usually heat
Voltage = Current x Resistance
V=IxR
Combine Series Resistance
R = R1 + R2 + .... Rn
Combined Parallel Resistance
1 ˜ R = (1 ˜ R1) + (1 ˜ R2) +......... (1 ˜ Rn)
Series
Parallel
Voltage
Divides
Same
Current
Same
Divides
Combined Resistance
High
Low
Fixed Resistors
Included in circuits in order to control the sizes of currents and voltages
Variable Resistors
Allows the resistance to be altered
Thermistors
A resistor whose resistance changes quite dramatically with temperature
Page 29 of 30
o Resistance decreases as temperature increases
o E.g.

Fire alarms
 Thermostats
Light-Dependant Resistors (LDRs)
Used in light sensitive circuits
o Resistance increases as light exposed increases
o E.g.
 Photographic equipment
 Automatic lighting controls 
Burglar alarms
Diodes
A resistor that behaves like a one-way valve or one-way streets
Resistance is low to current flowing in a particular direction
Resistance is high to current flowing in the opposing direction
o Used in circuits where it is important that current flows only in one direction
o E.g.
 Rectifier circuits that convert alternating current into direct current
Light Emitting Diodes (LEDs)
Diodes that glow when a current is flowing through them
OHM‟s Law
The current that flows through a conductor is directly proportional to the potential difference
across its ends, provided its temperature remains constant
Page 30 of 30