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IGCSE PHYSICS Section 1 General Physics
General PhysicsIGCSE Physics
Revision Book - Section 1
Name: _________________________________
Teacher: _________________________________
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IGCSE PHYSICS Section 1 General Physics
Syllabus Details________________________________
1.1 Length and timeCore• Use and describe the use of rules and measuring cylinders to calculate a length or a volume
THINGS TO REMEMBER... Always align your eye with the position being measured This avoids parallax errors
• Use and describe the use of clocks and devices for measuring an interval of time
THINGS TO REMEMBER... Remember there is always a reaction time associated with using a
clock or stopwatch
Supplement• Use and describe the use of a mechanical method for the measurement of a small distance (including use of a micrometer screw gauge)
Micrometers are used to measure small distances accurately
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IGCSE PHYSICS Section 1 General Physics
Micrometer
Vernier
• Measure and describe how to measure a short interval of time (including the period of a pendulum)
THINGS TO REMEMBER... For measuring short intervals of time (when each period is the
same), multiple measurements can be taken and then averaged
e.g. Period of a pendulum = Time for 10 oscillations / 10
1.2 Speed, velocity and accelerationCore• Define speed and calculate speed from total distance / total time
Symbol Definition SI unit
Vector / Scalar
Speed v or u Speed = total distance / total time m/s Scalar
• Plot and interpret a speed/time graph or a distance/time graph
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IGCSE PHYSICS Section 1 General Physics
Dis
tanc
e m
Time s
Constant speedStationary
Constant speed
Distance-Time Graphs
• Recognise from the shape of a speed/time graph when a body is– at rest– moving with constant speed– moving with changing speed
Spee
d m
/s
Time s
Changing SpeedConstant speed
Changing speed
Speed-Time Graphs
At rest
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IGCSE PHYSICS Section 1 General Physics
• Calculate the area under a speed/time graph to work out the distance travelled for motion with constant acceleration
Speed-Time Graphs
Area under graph = distance traveled
Spee
d m
/s
Time s
Distance A-B = ½ x v x t
Distance B-C = v x t
A
B C
• Demonstrate some understanding that acceleration is related to changing speed
Symbol Definition SI unit Vector / Scalar
Acceleration a Acceleration= change in velocity or speed / time
m/s2 Vector (for changing v)
• State that the acceleration of free fall for a body near to the Earth is constant
Acceleration of free fall near the Earth is constant
All objects near the earth fall with a constant acceleration The acceleration of free fall is NOT dependent on mass The acceleration is ~10m/s2
Supplement• Distinguish between speed and velocity
Symbol Definition SI unit
Vector / Scalar
Displacement s Distance moved in particular direction from a fixed point
m Vector
Velocity v or u Velocity = change in displacement / time m/s VectorSpeed v or u Speed = total distance / total time m/s Scalar
Speed has magnitude but no direction - SCALARVelocity has magnitude and direction - VECTOR
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IGCSE PHYSICS Section 1 General Physics
• Recognise linear motion for which the acceleration is constant and calculate the acceleration
Acceleration is constant if...
A constant resultant force actso Eg.
Objects falling in a vacuum
Equations that can be used for constant acceleration...
v=u+ats=[(u+v)/2]/tv2=u2+2ass=ut+1/2at2
s=vt-1/2at2
• Recognise motion for which the acceleration is not constant
Acceleration is NOT constant if...
A varying resultant force actso Eg.
Objects falling in air. The air resistance increases with velocity so the resultant force changes
A car accelerating. As the velocity of the car increases the air resistance also increases, so the resultant force changes.
• Describe qualitatively the motion of bodies falling in a uniform gravitational field with and without air resistance (including reference to terminal velocity)
Dis
plac
emen
t / m
Time / s
Velo
city
/ m
/s
Time / s
Acc
eler
atio
n / m
/s2
Time / s
g = ~10 m/s2
IN A VACUUM
Dis
plac
emen
t / m
Time / s
Acc
eler
atio
n / m
/s2
Time / s
Acceleration zero at terminal velocity
WITH AIR RESISTANCE
Velo
city
/ m
/s
Time / s
Terminal Velocity
Straight line as velocity become constant
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u Initial velocity v Final velocity a Acceleration t Time s Displacement
IGCSE PHYSICS Section 1 General Physics
1.3 Mass and weightCore• Show familiarity with the idea of the mass of a body• State that weight is a force
Weight (N) = Mass (kg) x g (N/kg)g = 10 N/kg (On the Earth)
• Weight is a force acting on objects because of gravity• Mass is related to the amount of matter• The Weight can be calculated by multiplying the mass by the strength of gravity
• Demonstrate understanding that weights (and hence masses) may be compared using a balance
SIMPLE BALANCE
A B
If Balance is in equilibrium then ….Weight of A = Weight of BMass of A = Mass of B
• Using standard masses the mass of unknown objects can be measured
Supplement• Demonstrate an understanding that mass is a property that ‘resists’ change in motion
5kg
10kg
5N
10N
a = 1m/s2
a = 1m/s2
As the mass increases…
• More force is needed for the same acceleration• The mass “resists” change in motion
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IGCSE PHYSICS Section 1 General Physics
• Describe, and use the concept of weight as the effect of a gravitational field on a mass
Earth(LARGE MASS)
mass
Gravitational field
Weight
A gravitational field shows a region in which a mass will feel a force due to another mass nearby
The Earth is a very large mass so a strong gravitational field exists around it
Weight is the force acting on a mass due to the Earth’s gravitational field
1.4 DensityCore• Describe an experiment to determine the density of a liquid and of a regularly shaped solid and make the necessary calculation
Density (kg/m3) = Mass (kg)
Volume (m3)
Density (kg/m3) = Mass (kg)
Volume (m3)
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mass
No Gravitational Field
No Weight
IGCSE PHYSICS Section 1 General Physics
Supplement• Describe the determination of the density of an irregularly shaped solid by the method of displacement, and make the necessary calculation
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IGCSE PHYSICS Section 1 General Physics
1.5 (a) Effects of forcesCore• State that a force may produce a change in size and shape of a body
Deformation
Force
Deformation
• Plot extension/load graphs and describe the associated experimental procedure
7 6
5
4
3
2
1
0
String
7 6
5
4
3
2
1
0
7 6
5
4
3
2
1
0
No Force
10NForce
20NForce
Exte
nsio
n / m
Load / N
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IGCSE PHYSICS Section 1 General Physics
• Describe the ways in which a force may change the motion of a body
Velocity increases in this direction
Before Effect of ForceApplied Force
Velocity = 0 m/s
F F
Unbalanced force
Velocity = 25 m/s No applied force Velocity = 25 m/s
Object Accelerates
No change to motion
Velocity decreases
Velocity = 0 m/s
F F
Balanced force
Velocity = 25 m/s Unbalanced force
No change to motion
Objects decelerates
F
100N100N
F
Velocity = 0 m/s
F F
• Find the resultant of two or more forces acting along the same line
2 N 5 N 3 N
2 N 2 N
Forces Resultant
0 N
2 N 5 N 6N
3 N
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IGCSE PHYSICS Section 1 General Physics
Supplement• Interpret extension/load graphs
Exte
nsio
n / m
Load / N
Read off load
Measure extension
• State Hooke’s Law and recall and use the expression F = k x
7 6
5
4
3
2
1
0
String
7 6
5
4
3
2
1
0
7 6
5
4
3
2
1
0
No Force
10NForce
20NForce
Exte
nsio
n / m
force / N
Hooke’s Law: Up to the elastic limit the extension of a spring is proportional to the tension force. The constant of proportionality is called the spring constant (k)
F = kx
• Recognise the significance of the term ‘limit of proportionality’ for an extension/load graph
Exte
nsio
n / m
Load / N
Limit of proportionality
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IGCSE PHYSICS Section 1 General Physics
• Recall and use the relation between force, mass and acceleration (including the direction)
Force (N) = Mass (kg) x Acceleration (m/s2)
F = maREMEMBER:
o Acceleration is a vector and so has directiono Force is a vector and so has direction
• Describe qualitatively motion in a curved path due to a perpendicular force(F = mv2/r is not required)
Tsinq
Pendulum
Perpendicular force provided by horizontal component of tension
Sun
EarthPerpendicular force provided by gravitational attraction of Sun
car
Perpendicular force provided by friction force between tires and road
Solar System
Car on a Corner
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IGCSE PHYSICS Section 1 General Physics
1.5 (b) Turning effectCore• Describe the moment of a force as a measure of its turning effect and give everyday examples
15m
2N2N
15m
Moment = Turning forceMoment (Nm) = Force (N) x perpendicular distance from force to pivot (m)
Anticlockwise Moment = 2N x 15mAnticlockwise Moment = 30Nm
Clockwise Moment = 2N x 15mClockwise Moment = 30Nm
• Describe qualitatively the balancing of a beam about a pivotSupplement• Perform and describe an experiment (involving vertical forces) to show that there is no net moment on a body in equilibrium• Apply the idea of opposing moments to simple systems in equilibrium
15m
2N3N
10m
Anticlockwise Moment = 3N x 10mAnticlockwise Moment = 30Nm
Clockwise Moment = 2N x 15mClockwise Moment = 30Nm
Anticlockwise moment = Clockwise moment
OBJECT IN EQUILIBRIUM - BALANCED
1.5 (c) Conditions for equilibriumCore• State that, when there is no resultant force and no resultant turning effect, a system is in equilibrium
FOR A SYSTEM IN EQUILIBRIUM: There is no resultant force and no turning effect
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IGCSE PHYSICS Section 1 General Physics
1.5 (d) Centre of massCore• Perform and describe an experiment to determine the position of the centre of mass of a plane lamina
Center of mass
Plane Lamina
Plum Line
Mass
Hang the lamina freely Hang a plum line from the position the lamina is hang from Draw a line along the plum line Repeat this procedure for another position
• Describe qualitatively the effect of the position of the centre of mass on the stability of simple objects
Stable Un-stable
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IGCSE PHYSICS Section 1 General Physics
1.5 (e) Scalars and vectorsSupplement• Demonstrate an understanding of the difference between scalars and vectors and give common examples
SCALAR VECTORProperty with magnitude but no direction
Property with magnitude and direction
Example:SpeedDistancePressureAreaVolumeWork
Example:VelocityAccelerationForceDisplacement
• Add vectors by graphical representation to determine a resultant• Determine graphically the resultant of two Vectors
1.6 (a) EnergyCore• Demonstrate an understanding that an object may have energy due to its motion or its position, and that energy may be transferred and stored
Energy... cannot be created or destroyed can be transferred from one form to another can be stored in to be transferred later
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IGCSE PHYSICS Section 1 General Physics
• Give examples of energy in different forms, including kinetic, gravitational, chemical, strain, nuclear, internal, electrical, light and sound
Energy Type Example
Kinetic Energy Moving objects (Car)Gravitational Potential Energy
Raised objects (Water in a dam)
Chemical Energy Energy stored in bonds (coal, oil)Strain Energy Energy due to flexing of materials (elastic band)Nuclear Energy Energy associated with atomic nuclei (Fission
reactors)Internal Energy Energy of materials – kinetic from particles moving
+ potential from bondsElectrical Energy Energy from moving charges (electricity)Light Energy Energy from Electromagnetic waves (light, IR)Sound Energy Energy due to vibrating particles (sound)
• Give examples of the conversion of energy from one form to another, and of its transfer from one place to another
Solar Energy
Photovoltaic CellElectrical Energy
Motor
Potential Energy
Kinetic Energy
• Apply the principle of energy conservation to simple examples
For any change to occur in nature energy must be transferred. Energy is not created or destroyed it is changed from one form into
another
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IGCSE PHYSICS Section 1 General Physics
Chemical Energy IN(Petrol)Kinetic Energy OUT
(Movement of car)
Thermal Energy LOST(Heat)
Total energy in = total energy outChemical Energy = Kinetic Energy + Thermal Energy
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IGCSE PHYSICS Section 1 General Physics
Supplement• Recall and use the expressions k.e. = ½ mv 2 and p.e. = mgh
1.6 (b) Energy resourcesCore• Distinguish between renewable and non-renewable sources of energy
Non-renewable: Energy sources that when used cannot be replaced (or at least it will take millions of years).e.g. Coal, Oil Natural gas.Renewable: Energy sources which can be used repeatedly without being used up. Solar energy, Wind, Tidal etc.
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IGCSE PHYSICS Section 1 General Physics
• Describe how electricity or other useful forms of energy may be obtained from:– chemical energy stored in fuel
Coal can be burnt to release thermal energy - which heats water and makes it move – which turns a generator – which generates electricity
– water, including the energy stored in waves, in tides, and in water behind hydroelectric dams
Water stored behind a dam or tidal barrier can be allowed to flow down – this moving water turns a generator – which generates electricity
– geothermal resources
Cold water is pumped underground – the earth warms the water which rises – this moving water turns a generator – which generates electricity
– nuclear fission
Atoms are split in a nuclear reactor – this releases energy which heats water – the water moves and turns a generator – which generates electricity
– heat and light from the Sun (solar cells and panels)
Solar energy from the sun can be converted directly into electricity using a solar cell
Solar energy can also be used to heat water directly (IR)
• Give advantages and disadvantages of each method in terms of cost, reliability, scale andenvironmental impact
Energy Source
Cost Reliability Scale Environmental Impact
Chemical (Coal)
Low Reliable Large High
Hydroelectric / tidal
High initially Reliable (unless a drought)
Large High
Geothermal High initially Reliable Small LowNuclear High Reliable Large LowSolar Energy High Unreliable
(only available during the day)
Small Low
• Show a qualitative understanding of efficiency
In any energy transfer process energy is “lost” to non-useful forms.
CAR: Chemical Energy is converted to kinetic energy (useful) + Thermal energy (waste)
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IGCSE PHYSICS Section 1 General Physics
Supplement• Show an understanding that energy is released by nuclear fusion in the Sun
Hydrogen-2
Hydrogen-3
Helium-4
neutron
+ENERGY
NUCLEAR FUSION IN THE SUN
In the Sun hydrogen nuclei fuse together to form helium nuclei In this process energy is released
• Recall and use the equation: efficiency = useful energy output / energy input × 100%
Efficiency = useful output energy / useful input energy
Percentage Efficiency = ( useful output energy / useful input energy ) x 100
In the transfer of energy from one form into another, there will always be losses, normally to heat energy.
The efficiency of the process tells use how much useful energy we get and how much is lost
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IGCSE PHYSICS Section 1 General Physics
1.6 (c) WorkCore• Relate (without calculation) work done to the magnitude of a force and the distance movedSupplement• Describe energy changes in terms of work done• Recall and use ΔW = Fd = ΔE
Force
Distance moved
Work done (J) = Force (N) x Distance moved (m)
Work done = Energy Transferred
DW = Fd = DE
EXAMPLES OF WORK BEING DONE
A car engine does work against friction and accelerating the car When you lift an object you do work against gravity
1.6 (d) PowerCore• Relate (without calculation) power to work done and time taken, using appropriate examplesSupplement• Recall and use the equation P = E/t in simple Systems
Power (W) = Energy Transferred (J)
Time (s)
P = E/t
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IGCSE PHYSICS Section 1 General Physics
1.7 PressureCore• Relate (without calculation) pressure to force and area, using appropriate examples
5kg5kg
5kg
50N 50N 50N
Low Pressure High Pressure
• Describe the simple mercury barometer and its use in measuring atmospheric pressure
The height of the mercury column relates to the atmospheric pressure
• Relate (without calculation) the pressure beneath a liquid surface to depth and to density, using appropriate examples
Pressure is dependent on the height and density of the column of water
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IGCSE PHYSICS Section 1 General Physics
• Use and describe the use of a manometerGas with unknown pressure
h = Atm P – Unknown P
gr
Liquid density r
Manometer
• Recall and use the equation p = F/A
PressureForce (N)
Area (or m2)
Pressure (N/m2) = Force (N)Area (m2)
p = F / A
• Recall and use the equation p = hρg
h
Liquid columnDensity = rHeight = hAcceleration due to gravity = g
Pressure = p = rgh
r
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