Download AQA Physics and Additional Science: P2 Revision checklist P2.1

AQA Physics and Additional Science:
P2 Revision checklist
P2.1 Forces and their effects
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/forces/
P2.1.1 Resultant forces
Whenever two objects interact, the forces they exert on each other are equal and opposite.
Forces that are acting at a point can be replaced by a single resultant force. Forces that are
acting in opposite direction subtract from each other. Forces that are acting in the same
direction add to each other.
If a resultant force acts upon a stationary object, it will accelerate.
If a resultant force acts upon a moving object, it will accelerate.
If there is no resultant force acting upon an object, it will remain stationary or travelling at a
constant velocity.
P2.1.2 Forces and Motion
The acceleration of an object depends upon the resultant force acting upon it and it’s mass.
F=ma or a=f/m
The gradient of a distance-time graph represents speed.
HT – Calculate the speed of an object using a distance-time graph.
Velocity is the speed in a given direction.
Acceleration is the rate of change of velocity a=change in velocity/time taken.
The gradient of a velocity-time graph represents acceleration.
HT – Calculate the acceleration of an object from the velocity-time graph.
HT – Calculate the distance travelled by an object by measuring the area under the graph.
P2.1.3 Forces and Braking
When a vehicle is travelling at a steady speed, the drag balances the driving force.
The greater the speed of a vehicle, the greater the force needed to bring it to a stop in the same
distance.
Stopping distance is the sum of the thinking distance and the braking distance.
A driver’s reaction time can depend upon tiredness, distraction, drugs and alcohol.
When the brakes are applied, work done by the brakes causes the kinetic energy of the vehicle
to reduce as it turns to heat energy in the brakes.
A vehicles braking distance can be affected by adverse road conditions, whether or maintenance
of the tyres or brakes.
P2.1.4 Forces and terminal velocity
The faster an object moves through a fluid (gas or liquid), the greater the frictional forces (drag)
that act against it.
An object falling through a fluid (e.g. a parachutist) will accelerate because the weight is greater
than the drag at first.
As a parachutist accelerates, the drag increases and the resultant force decreases. When the
weight and drag are equal, there is no resultant force and the parachutist reaches terminal
velocity.
Draw and interpret velocity-time graphs for falling objects.
Weight is mass x gravitational field strength w=m x g
P2.1.5 Forces and elasticity
A force may change the shape of an object.
Forces applied to a spring will cause the spring to stretch and store elastic potential energy
The extension of an elastic object is directly proportional to the force acting upon it provided
that the limit of proportionality is not reached.
F = k x e where k is thespring constant.
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AQA Physics and Additional Science:
P2 Revision checklist
P2.2 Kinetic energy
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/kinetic_energy/
P2.2.1 Forces and energy
Evaluate the benefits of different types of braking system, such as regenerative braking.
Evaluate the benefits of air bags, crumple zones, seat belts and side impact bars in cars.
Work done is the amount of energy transferred when a force moves an object a certain
distance. W = F x d
Power is the amount of work done in a given time. P = W / t
Gravitational potential energy is the energy stored within an object due to its height in a
gravitational field. G.P.E = m x g x h
When an object is raised through a height, work is done against gravity and so energy is
transferred to the object. The higher the object, stronger the gravitational field or more massive
the object, the more G.P.E is gained.
Kinetic energy is the energy stored within moving objects. K.E. = ½ x m x v2
P2.2.2 Momentum
Momentum is a property of moving objects. P = m x v
In a closed system, the momentum before a collision is equal to the momentum after the
collision.
Explain how momentum is conserved during collision and explosions.
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P2.3 Electricity
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/
P2.3.1 Static electricity
When insulating materials are rubbed together, electrons move from one surface to the other.
This causes a build- p of negative charge on one surface (due to the negative electrons building
up) and a positive charge to build up on the other surface (due to a lack of electrons).
When two charged objects become close they exert a force on one another.
If two similarly charged objects come close to one another they will repel (both +ve or both –ve)
Oppositely charged objects will repel.
Electrical charges can move easily through some substances e.g. metals.
P2.3.2 Electrical circuits
Current is a flow of electrical charge.
The size of electrical current is the amount of charge that passes a point in a second. It is
measured in Amperes (A). I = Q/t
The potential difference between two points is the amount of work done per unit of charge
between those points. It is measured in Volts. V = W/Q
Recall the circuit symbols for ammeter, voltmeter, cell, battery, fuse, switch, diode, resistor,
variable resistor, thermistor, light dependent resistor, L.E.D. and filament bulb.
Recall the describe the shape of the I-V graph for a fixed ohmic resistor, a diode and a filament
bulb.
The resistance of a component is the ratio of voltage to current across the component. R = V/I
or V = IR
The higher the resistance, the lower the current that can pass through a component for a
certain voltage.
For components in series :
 The resistance of the circuit is the sum of all resistances
 The current is the same everywhere in the circuit
 The potential different provided by the battery is shared between the components.
AQA Physics and Additional Science:
P2 Revision checklist
For components in parallel:
 The current splits at junctions and then combines before entering the battery.
 The current passing through each route will add up to the current passing through the
battery.
 The potential difference across each route is the same as the potential difference across
the battery.
The resistance of a filament bulb increases as the current passing through it increase due to the
temperature rise this causes.
The current will only pass through a diode in one direction.
An L.E.D. emits light when current passes through it.
The resistance of a light-dependent resistor decrease as light level increases.
The resistance of a thermistor decreases as the temperature increases.
P2.4 Mains electricity
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/
P2.4.1 Household electricity
Cells and batteries produce current that flows in one direction constantly. This is direct current
(D.C.)
The mains plug provides current which is constantly switching back and forth. This is alternating
current (A.C.)
HT – Interpret oscilloscope traces to calculate the period and frequency of alternating current.
Mains A.C. is approximately 50Hz and 230V.
Describe the layout and colour coding of a standard three-pin plug.
Describe the structure of 2 and 3-core electrical cable.
Fuses or circuit breakers will break the circuit is the current becomes too high.
If the current exceeds the rating of the fuse, it will melt and break the circuit.
Some circuits are protected by RCCD’s (Residual curren circuit breakers). These will break the
circuit much more quickly and can be reset without needing to be replaced.
P2.4.2 Current, charge and power
When current passes through a resistor the resistor gets hot.
Compact fluorescent lamps (CFL’s) waste less energy as heat and so are more efficient.
The power in an electrical circuit is given by: P = I x V
HT - The energy transferred in a circuit is given by: E = V x Q
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P2.5 Atoms and Radiation
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/atoms_radiation/
P2.5.1 Atomic structure
Atoms consist of a nucleus containing electrons and neutrons surrounded by orbiting electrons.
State the relative masses and charges of electrons, protons and neutrons.
In an atom, the number of protons and electrons is the same, resulting in no overall charge.
Atoms may gain or lose electrons causing them to become charged. These are Ions.
The number of protons in the nucleus is the atomic or proton number.
The number of protons and neutrons combined is the mass number.
Atoms with the same number of protons but different numbers of neutrons are called Isotopes
of the same element.
P2.5.2 Atoms and radiation.
Radioactive atoms give out radiations from their nuclei if they are unstable.
State the origins of background radiation.
State what alpha, beta and gamma radiation consist of.
HT – construct nuclear equations for alpha and beta decay.
AQA Physics and Additional Science:
P2 Revision checklist
Recall the Ionisation and penetrating powers of alpha, beta and gamma radiation as well as their
range in air.
Alpha and beta particles are deflected by magnetic fields as they are charged. Beta particles are
not affected as much as alpha particles.
State the uses and dangers associated with alpha, beta and gamma radiation.
Half-life of a radioactive substance is the amount of time it takes for it’s radioactive count rate
to halve from its initial value.
P2.6 Nuclear fission and fusion
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/atoms_radiation/
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/stars/
P2.6.1 Nuclear fission
Common fissionable fuels for nuclear reactors are Uranium-235 and Plutonium-239
Fission is the splitting of the nucleus to produce two smaller nucleus.
For fission to occur the nucleus must absorb a neutron. The fission process then releases two or
three further neutrons which can start other fission reactions. This begins and chain reaction.
P2.6.2 Nuclear fusion
Nuclear fusion is the joining of two nuclei to form one.
Nuclear fusion is the process by which energy is released in stars.
Stars gradually fuse small light such as hydrogen to eventually form heavier atoms such as
oxygen or Iron.
Stars form when gas is pulled together by the gravity.
The main sequence of a star’s life is where the forces within the star are balanced.
Describe the life cycle of medium and large stars.
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