1. AQA - GCSE Physics Revision
Additional Physics (P2)

2. Chapter 1 - Motion What you need to know: Distance-time Graphs
Finding out when an object is stationary
Finding out when an object is moving at a constant speed
Velocity and Acceleration
The difference between speed and velocity
What acceleration is and its units
What is deceleration
Velocity-time Graphs
Finding out if an object is accelerating or decelerating
What the area under a velocity-time graph represents
Using Graphs
Calculating speed from a distance-time graph
How we can calculate distance from a velocity-time graph
Calculating acceleration from velocity-time graphs

3. Distance-Time Graphs
A Constant Speed: An object moving at the same speed travels the same distance every second
Speed on a distance time graph is represented by the slope
Speed 1 = fast moving object (steep line)
Speed 2 = steady moving object (straight sloped line)
Speed 3 = stationary object (horizontal line)

4. Velocity and Acceleration
Velocity: speed in a given direction (2 objects can have the same speed but a different velocity due to the direction they are travelling in)
Acceleration: the rate at which the velocity of an object is increasing
An object travelling at a steady speed is accelerating if its velocity is changing
Deceleration = the velocity decreases (negative acceleration) and the object slows down

5. Velocity-Time Graphs
Distance Travelled = area under velocity-time graph
Acceleration and Deceleration = gradient of the lines
Finding the area under the graph
Break the area under the graph up into sections and work out the area of separate shapes
Once you have worked out the area of each shape add them together
*If you are only finding out the acceleration or deceleration you only need to work out the gradient of the sloping line (so only one triangle) Deceleration = -distance / time*

6. Summary How fast = Velocity How far = Distance
How quickly the velocity changes = acceleration
Object moving at a constant speed = an increased distance
Deceleration on a distance time graph

7. Chapter 2 – Speeding up and Slowing Down
What you need to know:
Forces Between Objects
When two forces interact what can we say about the acting forces
What is the unit of force
Resultant Forces
What is the resultant force
What happens when the resultant force is zero and what happens when it is not zero
Force and Acceleration
How acceleration depends on the size of the resultant force
What effect the mass of an object has on acceleration
On the Road
The resultant force of a vehicle travelling at a constant velocity
What the stopping distance of a vehicle depends on and how the stopping distance can be increased
Falling Objects
What is the difference between mass and weight
What is the terminal velocity

8. Forces Between Objects
Forces can:
Twist
Pull
Push
Upthrust
Weight/Gravity
Thrust
Friction
Forces are measured in Newtons (N)
They act in pairs
Each force acts in a certain direction
When two forces interact with each other they always exert equal and opposite forces on each other

9. Resultant Force Object at the Start Resultant Force
Resultant Force: working out the effect each force has on an object. This force has the same effect as all the forces acting on the object
Object at the Start
Resultant Force
Effect on the Object
1 (glider)
At rest
Zero
Stays at rest
2 (moving a crate)
Moving
Velocity stays the same
3 (plane)
Non-zero in the same direction as the direction of the moving object
Accelerates
4 (car breaking)
Non-zero in the opposite direction to the direction of the moving object
Decelerates

10. Force and Acceleration
Acceleration depends on:
The mass of an object
The amount of force applied F A M
Mass
Acceleration
Force
Resultant Force (N) = Mass (kg) x Acceleration (m/s²)
The velocity increases if:
The resultant force is in the same direction as the velocity
The velocity is positive
The velocity decreases if:
The resultant force is in the opposite direction as the velocity
The velocity is negative

11. Stopping Distance = Thinking Distance + Braking Distance
On the Road
Thinking Distance: distance travelled by the vehicle in the time taken for the driver to react
Braking Distance: distance the vehicle travels under the breaking force
The breaking force needed to stop a moving vehicle depends on:
The velocity of the vehicle
The mass of the vehicle
Stopping Distance = Thinking Distance + Braking Distance
Factors affecting the stopping distance are:
Tiredness
Alcohol and Drugs
Adverse Road Conditions
A Poorly Maintained Vehicle
Affect Thinking Distance
Affect Breaking Distance

12. Falling Objects Weight: the force of gravity upon an object (N)
Mass: the quantity of matter in it (kg)
The weight of an object:
Of mass 1kg = 10 N
Of mass 5kg = 50 N
The Earths gravitational field strength is 10 N/kg
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg))
If an object falls freely:
No other forces act upon it, therefore the resultant force is its weight. A 1kg object would accelerate at a constant acceleration of 10m/s² (force ÷mass) on previous slide
If an object falls in fluid:
The fluid drags on the object, and the drag force increases with speed
The resistance is weight – drag force
When the drag force and velocity are equal the object reaches a terminal velocity (the resultant force is 0 so the acceleration is 0)

13. Chapter 3 – Work, Energy and Momentum
What you need to know:
Energy and Work
What do we mean by ‘work’ in science
What is the relationship between work and energy
What happens to the work done against frictional forces
Kinetic Energy
What is kinetic and elastic potential energy
How does the kinetic energy of an object depend on its speed
How can we calculate kinetic energy
Momentum
How can we calculate momentum and what is its unit
What happens to the total momentum when two objects collide
More on Collisions and Explosions
Why does momentum have a direction and size
When two objects fly apart why is their total momentum 0
Changing Momentum
What does a force do to the momentum of an object
How can we calculate the change in momentum caused by force

14. Energy and Work
Workdone: when an object is moved by force we say that work is done to the object
It can also be the energy transferred/change in gravitational potential energy W D F
Force
Distance
Work Done
Work Done/Energy Transferred (J) = Force (N) x Distance (M) G H W
Weight
Height
Gravitational Potential Energy
Change of Gravitational Potential Energy(J) = Weight (N) x Change in Height (M)

15. Kinetic Energy
Elastic Potential Energy: the energy stored in a elastic object when work is done on the object
An object is elastic if it regains its shape after being stretched or squashed
Examples of this are:
Bow and arrow
Elastic band
Spring
Rubber swimming hats
Kinetic Energy (J) = ½ [Mass (Kg) x Speed²(m/s)]
KE = ½ mv²

16. Momentum
Momentum: the ability for an object to keep moving (relating its mass and velocity) in the same direction
Mass in motion P V M
Mass
Velocity
Momentum
It is difficult to change the direction of movement of an object with a lot of momentum
Momentum is conserved whenever objects interact, as long as no external forces act on them
What happens when two cars of the same mass collide?
If cars have a combined mass of 1000kg
Momentum is conserved (stays the same)
Velocity of car 1 is halved by impact
The momentum of a moving object(Kg m/s) = Mass (Kg) x Velocity (m/s)

17. More on Collisions and Explosions
Momentum has a size and a direction
When two objects push each other apart, they move apart with equal and opposite momentum
(Momentum of A) = -(Momentum of B) OR
(Mass of A x Velocity of A) = -(Mass of B x Velocity of B)
As it is travelling in the opposite direction
Changing Momentumm
The more time an impact takes, the less force is exerted

18. Chapter 4 – Static Electricity
What you need to know:
Electrical Charges
What happens when insulators are rubber together
What is transferred when objects are charged
What happens when charges are brought together
Charge on the Move
Why metals cant be charged by rubbing them
How charge is transferred through conducting materials
What happens when a charged conductor is connected to earth
Why do some objects sometimes produce sparks
Uses and Dangers of Static Electricity
In what ways is static electricity useful
How can static electricity be dangerous
How can we get rid of dangerous static electricity

19. Electrical Charges Van de Graaff Generator Charging by Friction
The dome charges up when the generator is switched on. Sparks are produced if the charge becomes to great. Charge builds up in the dome because:
The belt rubs against the felt pad (FRICTION)
The belt carries the charge onto the insulated metal dome
Sparks are produced when the dome can not hold any more charge
Charging by Friction
Rubbing two insulators together causes them to become charged
Friction causes electrons to be transferred from one material to the other
If a material:
Gains electrons it becomes negatively charged
Looses electrons it becomes positively charged
A Polythene Rod transfers electrons from the cloth to the rod
A Perspex Rod transfers electrons from the rod to the cloth
In the exam they will say which insulator carry’s which charge, unless it specifies which type of rod is being used (here you need to know which insulator transfers electrons)

20. Electrical Current: the rate of the flow of charge
Charge on the Move
Electrical Current: the rate of the flow of charge
Conductors can only be charged if they:
Off of the ground
Insulators can only be charged if they:
Brought into contact with a charged object
Discharging an Object
To discharge an object you have to provide a path between the conductor and the ground
The path between the object and the ground allows the electrons to flow to the ground – this object is then Earthed
(Shown in the diagram below)
If it is not insulated from the ground, it wont hold charge as electrons transfer between the conductor and the ground
Sparks and Strikes
If a metal object (conductor) gains to much charge it will produce a spark between the conductor and the charged object
This is because the voltage between the conductor and the ground increase
Lighting is an example of this

21. Uses and Dangers of Static Electricity
Uses of Static Electricity
Dangers of Static Electricity
Paint Sprayer:
The paint droplets are given positive charge
The car is given a negative charge
The droplet and car attract each other
The paint droplets repel each other
Transporting Oil:
If the pipe is not earthed, a build up of charge could cause a spark
If there is a spark, an explosion could occur
Photocopier:
Drum is positively charged until light falls on it
Charge is lost in the area where light hits it
Black toner sticks to the drum where there is still charge
Paper is heated to stick the toner to it
Antistatic Floors (in hospitals):
Some anaesthetics used in operating theatres are explosive
A spark could cause a explosion if any gas has escaped
Antistatic material is used on the floor to act as insulator (conducting charge to earth)
Electrostatic Precipitator:

22. Chapter 5 – Current Electricity
What you need to know:
Electric Circuits
What are the circuit symbols for common components
Resistance
The placement of ammeters and voltmeters
Resistance and its unit
‘Ohm’s’ Law
Reversing the current in a resistor
Current-Potential Difference Graphs
When the temperature changes what happens to the resistance in a filament lamp and thermistor
How does the current in a diode depend on the potential difference across it
When the light level increases what happens to the resistance of a LDR
Series and Parallel Circuits
The current and potential difference of components in a series circuit and parallel circuit
Why cells are connected in series
Finding the total resistance of a series circuit and parallel circuit

23. Electric Circuits-Symbols
A component diagram shows how the components in a circuit are connected together
Every component has its own symbol. The ones on this slide and the next are the ones you need for GCSE

25. Resistance
Resistance (ohms) = Potential difference (volts)
Current (amperes)
Ammeter: connected in series with the lamp to measure the current going through the lamp
Voltmeter: connected in parallel to measure the potential difference across the lamp
The current through a resistor of a constant temperature is directly proportional to the potential difference across the resistor

26. Current-Potential Difference Graphs
Thermistor: does no obey Ohm’s Law (is not a straight line) and a reverse of the filament lamp. More current = steeper graph, more heat = more free electrons to carry the current = increased current = reduced resistance
Filament Lamp: does not obey Ohm’s Law (it is not a straight line) more current = hotter = atoms vibrate faster increasing collisions with electrons = increased resistance (shown by the flattening out of the graph)
LDR: semi conductor. Increase in light = more electrons carrying current = increasing current = reduced resistance, little light = less electrons carrying current = reducing current = increased resistance
Diode: does not obey Ohm’s Law (is not a straight line) connected in a forward direction = low resistance, connected in the reverse direction = high resistance

27. potential difference/ the voltage of each cell
Series Circuit
The current is the same through all components in series with each other
The total potential difference/ the voltage supply in a series circuit is shared between
the components
The total potential difference/ the voltage supply of the cells is the sum of the
potential difference/ the voltage of each cell
The total resistance and the components in series is the sum of their separate
resistances

28. Parallel Circuit
The total current through the whole circuit is the sum of the currents through the separate components
For components in parallel, the potential difference/ the voltage across each component is the same
The bigger the resistance of a component the smaller the current

29. Chapter 6 – Mains Electricity
What you need to know:
Alternating Current
What direct and alternating current is
Frequency of the UK mains supply
Using an oscilloscope
Cables and Plugs
The casing of a mains plug
The colour of the different wires in a plug
Which wire is connected to different pins in a plug
Fuses
What are fuses and circuit breakers used for
Why do we have to use a fuse with the correct rating
Why appliances in plastic cases don’t need to be earthed
Electrical Power and Potential Difference
How to calculate the power of an appliance using energy and time
How we can calculate electrical power and its units
Finding the total resistance of a series circuit and parallel circuit
Electrical Energy and Charge (Higher)
What is electrical current and its charge
What energy transformations take place when charge flows through a resistor

30. Alternating Current (a.c)
Alternating Current: a current which repeatedly reverses in direction
You can measure the alternating potential difference using an oscilloscope
You can also see the peak potential difference as well as the frequency of an alternating current (Higher)
In the UK the frequency of mains electricity is 50 cycles per second (50hz)
Mains electricity uses an alternating current
In a mains circuit there is a live wire which is alternately positive and negative every cycle and a neutral wire which is always at 0 volts
Frequency = 1
Time (sec)

31. Cables and Plugs The pins in a plug are made of brass
Live Wire – is brown and connected to the live pin
Neutral– is blue and connected to the neutral pin
Earth Wire – is yellow and green and connected to the earth pin (a two core cable does not have a earth wire) which is the longest pin in the plug
The pins in a plug are made of brass
The cable is copper but is surrounded by an insulator such as rubber/flexible plastic
The case of the plug is made out of stiff plastic
Earth wires are essential for appliances with metal cases. If the live wire becomes loose and touches the metal case a large current flows to earth, blowing the fuse and breaking the circuit

32. Fuses
The fuse sits next to the live wire
A fuse is a safety device which breaks the circuit if the current becomes to high
It contains a thin wire which melts (breaking the circuit)
It is important that you use the correct amp fuse in your appliance.
If a larger fuse in used, the fuse will not blow when it is supposed to and the heating effect on the appliance could result in the appliance catching alight
Circuit Breakers
A circuit breaker is an electromagnetic switch that cuts the current off is the current is too great
After being used it can be reset
Circuit breakers work faster the fuses and are sometimes fitted into ‘fuse boxes’ to replace fuses

33. Electrical Power and Potential Difference
Power: energy transferred per second
The power (watts) is the energy transformed (joules) every second, using the equation below: E T P
Power (W) = Energy (J)
Time (S)
We can also calculate power dissipated (lost) in a device, using the equation below: P V I
Power (W) = Current (A) x Voltage (V)
Current
To make a light bulb shine brighter you can:
Increase the voltage (increase the energy delivered)
Increase the current (increase the rate at which energy is delivered)

34. Electrical Energy and Charge
Electrical Current: the rate of flow of charge (measured in Coulomb [C])
The charge of an appliance can be calculated using the equation below: C T I
Charge Flow (C) = Current (A) x Time (S)
Current
Resistor is connected to battery
Electrons pass through the resistor from the battery
Electrons are ‘resisted’ by the resistor
The atoms in the resistor gain kinetic energy
The resistor gets hot (electrical energy transferred as heat)
We can calculate the energy transformed using the equation below: E C V
Energy Transformed (J) = Potential Difference (V) x Charge Flow (C)

35. Chapter 7 – Nuclear Physics
What you need to know:
Nuclear reactions
How does the nucleus of an atom change when it emits and alpha or beta particle
How can we represent a nuclear reaction
Where does background radiation come from
The Discovery of the Nucleus (Higher)
How was the Nucleus model of the atom established
What other models of the atom were there
Nuclear Fission
What radioactive isotopes are used in nuclear power stations
What is nuclear fission
How is nuclear hear produced in a power station
What are fission neutrons
Nuclear Fusion
Where does the Sun’s energy come from
What happens during nuclear fusion
Why is it difficult to make a nuclear fusion reaction

36. Neutron changes into a proton (neutron lost = proton gained)
Nuclear Reactions
Alpha particles have 2 protons and 2 neutrons
An unstable particle becomes more stable by emitting an α particle 4 2 α
Neutron changes into a proton (neutron lost = proton gained)
Electrons is created and emitted -1 β
Background radiation:
Nuclear weapons testing
Nuclear power stations
Radioactive rocks – some of which give of radio active gases
Gamma radiation (which has no mass) is also given off by unstable nuclei after alpha and beta radiation is given off

37. The Discovery of the Nucleus
John Dalton reintroduced the idea that everything was made of atoms
He said atoms were solid spheres of matter that could not be split
Thomson adapted Dalton’s model
He said that an atom is a positively charged sphere with negative electrons distributed through it (plum pudding model)
1914 the nucleus was discovered
Alpha particles in a beam are sometimes scattered through large angles when they are directed at a thin metal foil e.g. gold foil
Rutherford’s gold foil experiment, meant the following could be discovered using his results:
The nucleus was positively charged as it repels the α particles (like charges repel like magnets)
Much smaller than the atom because most α particles pass through it without deflection
Where most of the mass of the atom is located
The paths the α particles take

38. Nuclear Fission: the splitting of an atomic nucleus
There are two elements, which cause nuclear fission when their nucleus split:
Uranium 235
Plutonium 239
When one fission actions occurs, the process repeats until the nucleus becomes stable, a chain reaction takes place
Nuclear fission is an un-natural process
In a nuclear reactor one neutron per fission (on average) goes on to produce further fission
Both used in making nuclear weapons
Nuclear Reactor

39. Nuclear Fusion
Nuclear Fusion: when two nuclei are forced close enough together so they form a single larger nucleus
Inside Fusion Reactors
The gas is heated by passing an electric current through it
The gas becomes so hot is forms a plasma of nuclei
The plasma is contained using a magnetic field to prevent it from touching the container walls
When hydrogen nuclei are fused together, helium is formed
Energy is required to make nuclear fusion occur
Energy is also released when two nuclei are fused together (which could be used to produce electricity)
Fusion reactors need to be at very high temperatures before nuclear fusion can take place
Fusion takes place in the sun, as the core is so hot it consists of nuclei without electrons resulting in them fusing together when they collide with enough kinetic energy otherwise they will repel each other
Fusion reactors are safer than fission reactors as:
The products (helium) are not radioactive therefore are stable
If the plasma touches the sides it immediately cools, meaning fusion can no longer take place