1
Q
What are the three states of Substances can exist as?
A
Solid
Liquid
Gas
2
Q
How many elements in Periodic Table?
A
118 elements
3
Q
What are the three main characteristics of an Element?
A
Made up of one type of atom.
Cannot be broken down into simpler type of matter.
Can exist as atoms or molecules.
4
Q
Describe the construction of an Atom?
A
Central core called the Nucleus made of Protons and Neutrons with Electrons orbiting around it in shells.
5
Q
What is the charge of a Proton?
A
Positive
6
Q
What is the charge of a Neutron?
A
No charge, they are neutral.
7
Q
What is the charge of an Electron?
A
Negative
8
Q
What is the mass of a Proton or Neutron?
A
1.67x10^-27kg
9
Q
What is the mass of an electron?
A
9.11x10^-31 kg
10
Q
What is the charge of an atom that has the same number of protons and electrons?
A
Neutral, no charge.
11
Q
How many electrons can the first 3 shells of an Atom hold?
A
First - 2
Second - 8
Third - 18
12
Q
What is the name for the outer most orbit (shell) of an atom?
A
The Valence Orbit
13
Q
What is the name for electrons in the outer most shell of an atom?
A
Valence Electrons
14
Q
If an atom has less than four electrons in its valence orbit then the the element is said to be?
A
A conductor
15
Q
If an atom has four electrons in its valence orbit then the the element is said to be?
A
A Semiconductor
16
Q
If an atom has more than four electrons in its valence orbit then the the element is said to be?
A
An Insulator
17
Q
What is the Atomic Number of an atom?
A
The number of protons in an atom.
18
Q
What is the Atomic Mass?
A
The amount of Protons and Neutrons in an atom.
19
Q
What is an Isotope?
A
An Isotope is an atom that has a different number of neutrons in the nucleus.
20
Q
Give two examples of an Isotope?
A
Carbon - 12 (has 6 neutrons)
Carbon - 14 ( has 8 neutrons)
21
Q
What is an Ion?
A
An Ion is an atom with charge, either negative or positive.
22
Q
What are the names for a positive and negative ion?
A
Positive Ions are called Cations
Negative Ions are called Anions
23
Q
What is a Molecule?
A
A Molecule is where two or more atoms are held together by chemical bonds.
24
Q
What is a Compound?
A
A Compound is where two or more elements are held together by chemical bonds.
25
What bond holds Molecules together?
Covalent bonds - mutual sharing electrons between two non-metal atoms
26
Name two examples of elements held together by Covalent Bonds?
H2O and CO2
27
What bond holds Compounds together?
Ionic Bonds - transfer of electrons between metal and non-metal atom
28
Give an example of a Compound held together by Ionic Bonds?
Sodium Chloride - NaCl
29
What are the three types of Mixtures?
Solutions (sea water)
Suspensions (sand in water)
Colloids (clouds)
30
What does the equation and letters of of p = m/v represent?
p = Denisty (kg/m^3)
m = mass
v = Volume
31
If heat is gained then the reaction is an..?
Endothermic Reaction
32
If heat is lost then the reaction is said to be an..?
Exothermic Reaction
33
What is the transition of a solid straight into gas called?
Sublimation
34
What is the transition of gas straight into a solid called?
Deposition
35
What is the transition of a liquid into a solid called?
Freezing / Fusion
36
What is the transition of a gas into a liquid called?
Condensation
37
What is the transition of a liquid into a gas called?
Evaporation
38
How many electrons does Titanium have?
22
39
What is a Mixture?
Two or more substances that are not chemically linked.
40
Describe how solids, liquids and gasses act in a container:
Solids hold their shape.
Liquids and Gasses take shape of the container.
41
Are the volumes fixed for solids, liquids and gasses?
Volume is fixed for Solids and Liquids
Volume isn’t fixed for Gasses
42
What are the units for Mass, Distance and Time?
Mass - kg
Distance - meters
Time - seconds
43
What are the units for Velocity and Acceleration?
Velocity - m/s
Acceleration- m/s^2
44
What is Weight?
Force acting downwards due to gravity measured in Newtons
45
What is the equation for Force and Weight?
Force = m x a
Weight = m x g
46
What is Force measured in?
Newtons
47
What is g and what value does g have unless otherwise stated?
g is the acceleration due to gravity with a value of 9.8 unless it says 10
48
What is meant by a Vector quantity?
Means it has both magnitude and direction.
49
What is a Moment?
A moment is a turning effect produced by a force acting at a distance.
50
What is an opposing moment?
Moments that act against each other.
51
What is a Couple?
A pair of parallel forces equal in magnitude but opposite in direction.
52
What’s the equation for a Couple?
T = F x r x 2
53
What is the equation for a Moment?
M = F x s
54
What is the equation for a beam in equilibrium?
F1 x S1 = F2 x S2
55
What is the Resultant force of moment?
The effect that results from two or more vectors of the same type acting on an object.
56
What is Impulse and is it a vector?
Impulse is the product of force and time.
Impulse is a vector quantity.
57
What is a Scalar quantity?
A quantity that has magnitude but no direction.
58
What is the formula to find the amount of electrons in an atoms shell?
2n^2
n being the number of shell
59
What are the three steps to calculate the Center of Gravity from a datum using moments?
Calculate induvidual moments
Sum the individual moments
Divide Total Moment / Total Weight
60
What does Stress describe?
Stress describes the magnitude of forces that cause deformation
61
What does Strain describe?
Strain describes the deformation of a material due to stress.
62
What are the 5 structural stresses aircraft endure?
Tension
Torsion
Sheer
Bending
Compression
63
What is Elasticity described as?
Elasticity is the ability of a material to return to its original shape once external forces are removed.
64
What is Tension described as?
Tension is the stress applied that tends to increase the length of the body.
65
What is Hooke’s Law?
The extension of an elastic object is directly proportional to the force applied to it.
66
What is Young’s Modulus?
Young’s Modulus (E) is a constant that represents the ratio of Stress / Strain
67
What is the equation for Stress?
Stress (N/m^2) = Force (N) / Cross-sectional Area (m^2)
68
What is the equation for Strain?
Strain = Extension (Change of length) (m) / Original Length (m)
69
What is the equation for Hooke’s Law?
Force (N) = Spring Constant (k) (n/m) x Extension (e) (m)
70
What is the Elastic/ Proportional Limit?
The point at where permanent deformation occurs.
71
What is the Elastic Region?
The linear section of the graph where the ration of stress / strain will be constant as Hooke’s Law applies.
72
What is the Plastic Region?
The region where the force applied and the deformation are not proportional.
73
Where do the stresses of bending, compression and tension act on an aircraft’s wings when it’s on the ground and when it’s in the air?
In the Air:
Bending of the wing upwards
Compression on top of the wing
Tension under the wing
On Ground:
Bending of the wing downwards
Tension on top of the wing
Compression under the wing
74
What’s the relationship between force and extension?
Proportional
75
What’s the equation for Pressure?
Pressure = Force / Cross-sectional area
76
Describe Hardness?
Tendency to resist indentation.
77
Describe Strength?
Tendency to withstand an applied load without failure or deformation.
78
Describe Toughness?
Tendency to resist breakage when deforming or when subjected to impact forces.
79
Describe Brittleness?
Tendency to break without change of shape.
80
Describe Plasticity?
Tendency to remain in the new shape once distorting force is removed.
81
Describe Malleability?
Tendency to undergo compressive stress without damage.
82
Describe Ductility?
Tendency to undergo tensile stress without damage.
83
Describe Vapour?
A gas that can be liquified by an increase in pressure without decreasing its temperature.
84
Describe Volatile?
A volatile liquid is one which readily evaporates at normal temperature.
85
Describe Flammability?
A flammable material is one of that will catch fire readily.
86
Describe Flashpoint?
The flashpoint of a combustible liquid is the temperature at which it will catch fire when exposed to a naked flame.
The lower the flash point the easier it is to ignite the material.
87
Describe Toxicity?
The toxicity of a substance refers to how poisonous it is.
88
Describe Inert?
An inert substance is one that will not chemically combined with another substance.
89
1 atmosphere is equal to? (6 Things)
14.7 PSI
760mm of Mercury
1.01 Bar
101325 Pascal
1013.25 hPA Hectopascals
1013.25 mb Millibars
90
What is the equation for Absolute Pressure?
Absolute Pressure = Gauge Pressure + Atmospheric Pressure
91
What is the Buoyant Force?
The Buoyant force is equal to the weight of fluid displaced.
92
What is the equation to find out what percentage of an object is under the water when floating?
(Density of Object / Density of Liquid) x 100 = Percentage below surface
93
What is Newtons First law?
An object will not change its motion unless a force acts on it.
94
What is Archemidies Principle?
When an object floats, Buoyant force is equal to weight of object displaced.
95
What is the name for turning effect of a static body?
A moment
96
What is the name for a turning effect for a body in motion?
A torque
97
What do the letters represent in SUVAT?
S = Distance / height (m)
u = Initial Velocity (m/s)
v = Velocity (m/s)
a = Acceleration (m/s^2)
t = Time (s)
98
What are the three SUVAT equations to remember?
s = (u+v)/2 x t
v = u + at
s= ut + 1/2 at^2
99
What is the Centripetal force?
The Centripetal force is the force needed to keep an object moving in a curved path and is directed towards the centre of the curved path.
100
What is the formula for the Centripetal force?
Fc = mv^2 / r
101
What is the Centrifugal force?
Centrifugal force is the apparent outwards force a body travelling on a curved path feels.
102
If the speed of an object undergoing uniform circular motion is the same, why is its velocity constantly changing and why is it always accelerating?
An object that travels with a constant speed but different direction is always accelerating and has a different velocity.
103
What is the difference between Centripetal force and Centrifugal force?
Centripetal acts towards the centre
Centrifugal acts outwards
104
What is the Angular Amplitude?
Angular displacement from rest to maximum swing position.
105
What is Oscillation / Vibration in terms of pendulum
One complete swing to and from maximum position
106
What is the Length of the Pendulum?
Distance from the pivot to the centre of gravity of the bob.
107
What is the periodic time?
Time taken to complete one oscillation
108
What is a cycle in terms of pendulums?
The motion completed in one period.
109
What is the frequency of a pendulum?
The number of cycles completed in unit time
110
Does the mass of the Bob affect the periodic time of a pendulum?
No
111
What is the relationship of Periodic Time and Length?
Inversely Proportional
112
What is the relationship of the square of the periodic time and length?
Proportional
113
What is Damping?
Decrease of vibrations through resistance to motion
114
What is a Vibration?
A Vibration is a mechanical oscillation about an equilibrium point
115
What are Harmonics?
Periodic Vibrations
116
What is the Fundamental Frequency?
The lowest frequency of a periodic wave.
117
What is Resonance?
The tendency of a system to oscillate at maximum amplitude at a certain frequency.
118
How many wavelengths does the first harmonic produce?
Half a wavelength.
119
How many wavelengths does the second harmonic produce?
One wavelength
120
How many wave lengths does the third harmonic produce?
One and a half wavelengths
121
How many wavelengths does the fourth harmonic produce?
Two wavelengths
122
What is the equation for Periodic Motion?
T = 2Pi x Sqr (L/g)
123
What is a Free Vibration?
A free vibration is where a body is disturbed and then left alone to vibrate.
124
What is a Forced Vibration?
A forced vibration is where a body vibrates due to a repeating external force.
125
What is the flashpoint of Aviation fuel and Petroleum?
Av Fuel - 38 degrees
Petrol - -23 degrees
126
How do you convert 18km/h into m/s?
You convert the 18km in 18,000m and convert the hour into 3600 seconds then divide 18,000/3600 which gives you 5m/s.
127
What is the SI unit for Spring Constant?
Newtons Per Meter
N/m
128
What is the Velocity Ratio?
The velocity ratio is how far the effort has to move in relation to the load.
129
What is Mechanical Advantage?
Mechanical Advantage is the ratio of force produced by pulley to the force applied to it.
130
What is the Actual Mechanical Advantage?
The AMA is the ratio of output force and input force.
131
What is the Ideal Mechanical Advantage?
The IMA is the mechanical advantage that would exist if there was no friction in the pulley.
132
What is a Lever?
A rigid bar capable of turning about a fulcrum.
133
What are the three types of Levers?
First Class
Second Class
Third Class
134
What is the acronym to remember the set up of the three types of Levers and what does it mean?
FLE is the acronym.
F represents 1st class and shows the fulcrum is in the middle.
L represents 2nd class and shows the load is in the middle.
E represents 3rd class and shows the effort is in the middle.
135
Give an example for all 3 classes of Levers?
1st - See-saw
2nd - Wheel Barrow
3rd - Aircraft Landing Gear
136
What is the equation for Velocity Ratio?
VR = S in / S out
VR = Distance In (Effort) / Distance Out (Load)
137
What is the equation to workout the Mechanical Advantage?
MA = Force Out (resistance or load) / Force In (effort)
138
What is the equation for the Actual Mechanical Advantage?
The same as mechanical advantage.
AMA = Force Out (resistance or load) / Force In (effort)
139
What is the equation for Ideal Mechanical Advantage?
The same as Velocity Ratio.
IMA = Distance In (Effort) / Distance Out (Load)
140
Define when Work is done in terms of force?
Work is done when a force causes movement of an object.
141
Define what Power is?
Power is a measure of the rate at which work is done or energy is converted.
142
What is Energy?
Energy is the capacity to do work.
143
What is Potential Energy?
Potential Energy is the energy a body has due to its position.
144
What is the equation for Potential Energy and its Units?
E = m (mass kg) x g (acceleration due to grav) x height (meters)
E = mgh
Units: Joules
145
What is Kinetic Energy?
Kinetic Energy is the energy a body has due to its motion.
146
What is the equation for Kinetic Energy and its Units?
E = 1/2 x mass x velocity^2
E = 1/2 mv^2
Units: Joules
147
What is Toal Energy?
Total Energy is the sum of all different forms of energy in a system.
148
What is Chemical Energy?
Chemical Energy is the energy stored in the chemical bonds between atoms.
149
What is Heat?
Heat is the thermal energy that a body possesses.
150
What is Efficiency?
Efficiency is the ratio of useful work done.
151
What is Newtons First Law?
A body in motion stays in motion unless acted on.
152
What is Newtons Second Law?
F = m x a
153
What is Newtons Third Law?
Every action has an equal and opposite reaction.
154
What are Spur Gears?
Have teeth cut into circumference and used to connected parallel shafts.
155
What are Bevel Gears?
Bevel Gears have teeth cut into a conical surface, used to transmit power between two shafts at an angle to one another.
156
What are Worm Gears and what are they good for?
Worm gears consist of a short revolving cylinder (worm) that is driven.
They are good for large reductions in speed.
An example of a worm gears is a Jubilee Clip
157
What are Sun and Planetary Gears and what are they good for?
A series of gears with a stationary gear at the outer edge with a central sun gear that drives multiple planetary gears between the sun and outer edge.
Good for speed reduction
158
What is the Mechanical Advantage of a Fixed Pulley?
A fixed pulley has a mechanical advantage of 1
159
What is the Mechanical Advantage of a Moveable Pulley?
A moveable pulley has a mechanical advantage of 2.
160
What is the mechanical advantage of a block and tackle pulley?
A block and tackle pulley had a mechanical advantage of 3
161
In a SUVAT what does the constant g represent?
The acceleration due to gravity
162
What is 1 Joule in Watts?
1 Watt is equal to 1 Joule
163
How can you find efficiency with just the Mechanical Advantage and the Velocity Ratio?
Efficiency = Mechanical Advantage / Velocity Ratio
164
What is the equation for Power?
Power = Work Done / Time
165
What is the equation for the centripetal acceleration?
Ac = v^2 / r
166
Define the type of quantity and what Momentum is?
Momentum is a vector quantity that describes mass in motion.
167
What is the equation for Momentum?
p = m x v
168
What are the SI units for Momentum?
Kg m/s
169
What is the conservation of Momentum?
Momentum before = momentum after so momentum is said to be conserved.
170
What is the equation for the conservation of momentum?
m1u1 + m2u2 = m1v1 + m2v2
171
What gets transferred when two bodies collide in terms of momentum?
Kinetic Energy and Momentum
172
What are the two types of collisions?
Elastic and Inelastic
173
What is an Elastic Collision?
An Elastic Collision is a collision where kinetic energy is conserved and the body’s don’t stick together.
174
What is an Inelastic Collision?
An Inelastic Collision is a collision where kinetic energy isn’t conserved and the two body’s stick together.
This means the two body’s have the same speed after the collision.
175
What is the Impluse?
The impulse is:
force acting for a period of time
Or
change of momentum
176
What is the Impulse equal to?
Impulse is equal to the product of force and contact time, and the product of mass and change in velocity (change in momentum)
J = Ft = m x change in v
177
What is the Si unit for Impulse?
Ns
Newton Seconds
178
What is the equation for an Elastic Collision?
m1u1 + m2u2 = m1v1 + m2v2
179
What is the equation for an Inelastic Collision?
m1u1 + m2u2 = (m1 + m2) x v
180
Describe what Friction is?
Friction is the force resisting the relative motion of materials contacting each other.
181
What are the 3 types of Friction?
Starting
Sliding
Rolling
182
What are the 2 equations for Friction?
F = u x N
Force = coefficient of friction x normal force
F = u x W
Force = coefficient of friction x weight
183
How many coefficients of friction does a pair of surfaces have?
Every pair of surfaces as 3 coefficients of friction
184
What is Starting Friction?
Starting friction is the friction when a body at rest starts to move
185
What is Sliding Friction?
Sliding Friction is the friction when a body is sliding over a surface
186
What is the Rolling Friction?
Rolling Friction is the friction of a body as it rolls on a surface.
187
Describe the make up of a Gyroscope?
A spinning rotor rotating about an axis at a high speed with gimbals around it that allow it to rotate and keep its rotational axis the same.
188
What are the two important properties of a Gyroscope?
Rigidity and Precession
189
What is Gyroscopic Rigidity?
Rigidity is the ability of a spinning rotor to stay rotating in its axis in space unless acted on my an external force.
190
What 4 factors affect the Rigidity of a spinning rotor?
Rotor Mass
Effective Radius that mass acts at
Speed of Rotation
Bearing Friction
191
What is another name for rigidity in a gyroscope?
Gyroscopic Inertia
192
What is Gyroscopic Precession?
Precession is where an external force is applied to the gyro and the gyro resists the change and moves the force applied at right angles to the direction originally applied.
193
What are gyroscopes used to measure in aircraft?
Gyroscopes are used to measure or maintain orientation or angular velocity
194
What do gimbals allow gyroscopes to do?
Gimbals allow the enclosure of the gyroscope to be rotated or flipped whilst keeping the rotor spinning along the same axis.
195
What does a Vertical Gyroscope measure on an aircraft?
VG measure the aircraft’s pitch and roll attitude relative to the horizon.
196
Describe what Density is?
Density is a measure of how closely packed the particles are.
197
What is Specific Gravity?
Specific gravity (relative density) compares the density of the two substances.
198
What are the two equations for Specific Gravity?
SG = p1 / p2
SG = W1 / W2
199
The density of all liquids and solids are compared to..?
Water at 4 degrees C
200
The density of all gasses are compared to..?
Air at room temp (20 degrees C)
201
What are the SI units for Pressure?
Pa or N/m^2
202
What is the speed of sound at sea level?
340 m/s
203
What does ISA stand for?
International Standard Atmosphere
204
When doe aircraft feel the compressive effects of air?
When they go at or past the speed of sound.
205
What happens to a liquids when they are compressed?
Increases the pressure, increases the temperature and reduces the viscosity.
206
Describe the relationship of temperature and viscosity in fluids?
Inversely proportional
207
Describe the relationship of temperature and viscosity in gasses?
Proportional
208
What is Fluid Pressure?
The pressure that a fluid feels
209
What is the formula for fluid pressure?
P = pVg
Pressure = density x volume x gravity
210
What is the relationship of pressure and depth of a fluid?
Proportional
211
What is Pascals Law?
Pascals Law says that when pressure is applied to a liquid in a container, the liquid exerts an equal force at right angles to the container.
212
What is the equation for pressure?
Pressure = Force / Cross sectional area
213
What is a Differential Areas?
The difference in surface area between two sides of a piston.
214
What does a reading of 1000 mean on a Hydrometer?
Means that the float is immersed in pure water.
215
What does it mean if the float in a hydrometer reads more or less than 1000?
If more than 1000 liquid has higher specific gravity
If less than 1000 liquid has lower specific gravity
216
When a battery is discharged, what does the float read in a hydrometer?
1150
217
When a battery is charged, what does the float read in a hydrometer?
1275 - 1310
218
Define Viscosity?
Opposition to flow of a liquid caused by internal friction of molecules.
219
What is the equation to find Viscosity?
n = Pa x s
Viscosity = Pascals x Seconds
220
What is the SI units for Pressure Velocity?
Pascal Seconds (PaS)
Kilograms per meter seconds (kg/ms)
221
What happens to the viscosity of a liquid as temperature increases?
The viscosity decreases
222
What is Fluid Resistance?
Fluid resistance or fluid friction is the resistance that is felt on a solid as it travels through a liquid or gas, or when a liquid or gas travels through a solid.
223
What factors affect the amount of fluid resistance on a solid object?
Viscosity of the Fluid
Surface Texture
Shape
224
What is Streamlining?
Streamlining means decreasing the amount of restrictive force of fluid friction.
225
What is the Normal Force?
The normal force is the force equal to that that is subjected to an item
226
What is Static Pressure?
Static Pressure is the sum of gravity, applied force and atmospheric pressure of a fluid at rest.
227
What is Dynamic Pressure?
Dynamic Pressure is the pressure due to the velocity of the fluid in motion.
228
What is total pressure?
Total pressure is the sum of dynamic and static pressure.
229
An increase in velocity of a fluid means that the fluid has..?
a lower pressure.
230
A decrease in velocity of a fluid means that the fluid has..?
A higher pressure.
231
Bernoulli’s theorem states that?
The static pressure and potential energy of a fluid in motion decreases when kinetic energy or velocity increases.
232
What is the Venturi effect?
The Venturi effect demonstrates how a fluid increases its kinetic energy when it enters a constriction.
233
What 3 forms of energy can be identified when a Fluid moves through a Venturi Tube?
The GPE of the particles
The PE of the pressure in the fluid
The KE due to the movement of the particles
234
What can Venturi Tubes be used for on aircraft?
Venturi tubes can be used to operate gyroscopic instruments.
235
What two sections of the Venturi tube do we care about and which equation satisfies this?
The Convergent and Divergent sections.
Epot 1 + Epres 1 + Ekin 1 = Epot 2 + Epres 2 + Epres 2
236
What is Bernoulli’s equation?
P1 + 1/2 x pv^2 = P2 + 1/2 x pv^2
237
What is the equation to calculate lift?
Lift = Difference in Pressure x Area of Wing
F = Delta P x A
238
What does the pressure of a column depend on?
The pressure of a column depends on the height of a column, not the volume of it
239
What are the three methods of Heat Transfer?
Convection
Conduction
Radiation
240
What is the equation for Specific Heat Capacity?
Q = m x c x delta t
241
What are the 3 equations used to find Work done?
W = F x s
W = P x A x s
W = P x delta V
242
What is temperature a measure of?
Temperature is the measure of the average kinetic energy of the particles.
243
What is a Thermometer?
Thermometers are temperature measuring instruments
244
What are the 4 types of Thermometer?
Thermocouple
Bimetallic
Bulb
Thermistor
245
What is a Thermocouple and where is it used?
Thermocouples are temperature sensors used to measure high temperatures.
They are used as exhaust gas temp sensors.
246
What is a Bulb Thermometer?
A Bulb Thermometer is a temperature measuring device containing mercury that expands at a linear rate.
247
What is a Bimetallic Thermometer?
A Bimetallic Thermometer is a temperature sensor that uses a bimetallic strip to show temperature as mechanical displacement.
248
What is a Thermistor?
A Thermistor is a temperature sensor that changes its electrical resistance with changes in temperature.
249
What are the 3 temperature scales?
Celsius
Fahrenheit
Kelvin
250
What is the freezing and boiling point of water in Celsius?
0 and 100
251
What is the freezing and boiling point of water in Fahrenheit ?
32 and 212
252
What is the freezing and boiling point of water in Kelvin?
273 and 373
253
What is the only temperature that Celsius and Fahrenheit are the same at?
-40
254
What is Kelvin?
Kelvin is the base unit of temperature in SI units
255
What is 0 Kelvin?
0 Kelvin is absolute zero.
This is the lowest possible temperature anything can ever be.
256
What is 0 Kelvin in Celsius?
-273 degrees C
257
What is the equation to convert Fahrenheit to Celsius?
C = 5/9 x (F-32)
258
What is the equation for Celsius to Fahrenheit?
F = 9C / 5 +32
259
What is the equation of Celsius to Kelvin?
K = C + 273
260
What is the difference in Kelvin on 20c and 25c?
5K since Kelvin and Celsius are in the same scale.
261
How to workout difference in degrees Celsius of two Fahrenheit values?
Convert both Fahrenheit values to degrees Celsius then find the difference of the two Celsius values.
262
How do you convert a Fahrenheit value into Kelvin?
Fahrenheit to Celsius, then Celsius to Fahrenheit.
There is no direct F to K equation.
263
What is Heat defined as?
Measure of energy transferred.
264
What is the definition of Specific Heat Capacity?
The amount of energy required to raise the temperature of 1kg of substance by 1 K or degrees C.
265
What is Linear Expansion?
Linear Expansion: An object that is heated or cooled expands proportionally to the original length and change in temperature.
266
What is the equation for Linear Expansion?
Change in Length = Alpha x Original Length x Change in Temperature
267
What does the constant alpha represent in expansion?
Alpha represents the Coefficient of Thermal Expansion for a substance.
268
What is Volumetric Expansion?
The same as Linear Expansion but where all sides of the 3d shape feel the expansion, this means that we have 3 times the constant alpha.
269
What is the equation for Volumetric Expansion?
Change in Volume = 3 Alpha x Original Volume x Change in Temperature.
270
What is the First Law of Thermodynamics?
Energy conservation.
Energy In = Energy Out
271
What is the Second Law of Thermodynamics?
Total energy output = Amount of heat supplied
272
What are the three processes in the Engine where changes in pressure, temperature and density occur?
Compression
Combustion
Expansion
273
What is Boyle’s Law?
Boyle’s Law states that: the Pressure and Volume of a gas at a Constant Temperature are inversely proportional.
274
What is Charles’s Law?
Charles’s Law states that: the Volume and Temperature of a gas at a Constant Pressure are proportional.
275
What is Gay-Lussac’s Law?
Gay-Lussac’s Law states that: the Temperature and Pressure of a gas at a Constant Volume are proportional.
276
What is the equation for the Combined Gas Law?
PV/T = k
PV - Boyle’s Law
P/T - Gay-Lussac’s Law
V/T - Charle’s Law
277
What do these 4 different processes mean?
Isochoric
Isobaric
Isothermal
Adiabatic
Isochoric - Constant Volume
Isobaric - Constant Pressure
Isothermal - Constant Temperature
Adiabatic - No heat transfer
278
What 2 things can happen in Isothermal Expansion and Compression to maintain temperature?
If gas is compressed, pressure will increase to maintain temperature.
If gas is expanding, pressure will decrease to maintain temperature.
279
What is an Adiabatic Process?
An Adiabatic process is one where no heat is transferred to or from a system.
It is an idealisation.
280
What is a Reversible Process?
A process where system can be restored to oringal state without changes to surroundings.
281
What is an Irreversible Process?
A process that cannot be restored without causing changes to surroundings.
282
What are the two types of cycles for Internal Combustion Engines?
Reciprocating Piston Engines - Use non-flowing processes that convert heat energy into mechanical energy.
Gas Turbine Engines - Use flow processes to convert heat energy into mechanical energy.
283
What is the Otto Cycle?
Idealised Thermodynamic Cycle of a piston engine where air behaves as a perfect gas.
284
What happens in the 4 stages of the Otto Cycle?
1-2: Adiabatic Compression - Piston moves from bottom to top, no heat transfer occurs, pressure and temperature increase, volume decreases.
2-3: Reversible Isochoric Heating - Piston is at top, ignition of fuel-air mixture takes place, temperature and pressure increase, volume is constant.
3-4: Adiabatic Expansion - Increased pressure pushes piston down, air expands and does work on piston, pressure and temperature decrease. No heat transfer occurs.
4-1: Reversible Isochoric Rejection - Piston is at the bottom, pressure and temperature decrease to original value.
285
What are the Constant Volume and Constant Pressure processes said to be for a perfect gas?
A reversible process.
286
What is an example of the refrigerant used in a fridge?
Freon
287
How does a refrigerator work?
Compressor- Refrigerant in gas form enters the compressor at a low pressure and leaves with an increased pressure and temperature.
Condenser - New high temp and pressure refrigerant goes through condenser coils that are being blows with warm outside air, the gas gives some of its heat to the air being blown over the coils and condenses into high pressure liquid.
Expansion Valve - High pressure liquid refrigerant flows through expansion valve which restricts flow and lowers the pressure. Liquid refrigerant leaves at a lower pressure and at a lower temperature than surrounding air.
Evaporator - Fluid then moves to evaporator coils where heat from inside fridge is absorbed by liquid and boils it. The air going over the evaporator is cooled. The process then repeats.
288
What direction does heat flow?
From higher to lower temperature.
289
How can you make a low temperature go to a higher temperature?
Add additional heat energy through a pump or compressor.
290
What is Sensible Heat?
The heat that causes an objects temperature to change.
291
What is Latent Heat?
Latent Heat is the amount of heat absorbed or released when a body undergoes a constant-temperature process.
292
Where is Sensible Heat and Latent Heat on a graph of Time against Temperature?
Sensible heat is the diagonal lines that show an increase or decrease in temperature.
Latent heat is the flat lines that show a change in state.
293
Why is the graph at a constant temperature when changing state?
The temperature of a substance stays constant until all of it has changed state.
294
Define what Refrigeration is?
Refrigeration is the removal and relocation of heat.
295
What does a Heat Pump do?
Heats an area rather than cool it.
296
What is the gas law that relates to Constant Temperature?
Boyles Law
297
What is the gas law that relates to Constant Pressure?
Charles’s Law
298
What is the gas law that relates to Constant Volume?
Gay-Lussac’s Law
299
Which Gyroscopic property is subject to Newton’s first law?
Gyroscopic Rigidity
300
What is a trick to know if something is a vector or a scalar quantity?
If it sounds fancy then it’s a vector.
E.g. Speed is scalar, velocity is vector
301
What is Light?
Light is electromagnetic radiation.
302
What will the wavelength and colour of light be if it has a high frequency?
The higher the frequency, the lower the wavelength and the bluer the light will be.
303
What will the wavelength and colour of light be if it has a lower frequency?
The lower the frequency, the higher the wavelength and the redder the light will be.
304
What scale are light waves measured in?
Nanometers and Angstroms
305
Wavelengths between blank and blank are visible?
400 and 700
306
Wavelengths greater than 700 or less than 400nm are..?
Not visible to the naked eye.
307
What is the speed of light?
300 million m/s
3x10^8
308
When light passes through a material the lights speed..?
Decreases.
309
When does the speed of light change?
When it travels through a different medium.
310
What is the equation for the speed of light?
C = wavelength x frequency
311
If a question doesn’t give a C value, use for the speed of light, what do we take the speed to be?
3x10^8 m/s
312
Where does Reflection occur?
Reflection occurs at a plane surface.
Mirror or Glass
313
What are the two things to remember about the Law of Reflection?
Angle of Incidence is equal to angle of Reflection
Incident ray, reflected ray and normal line all lie on the same plane.
314
What are images created by a mirror or lens said to be?
Real or Virtual
315
What is a Convex mirror?
A mirror that curves outwards towards the light source.
316
What is a Concave mirror?
A mirror that curves inwards away from the light source.
317
What is Refraction?
Refraction is the change in direction of a wave when it enters a different medium.
318
What is the Refractive Index of a material?
The Refractive Index is the ratio of the speed of light in a vacuum to the speed of light in the material.
319
What will happen to light entering a material with a high refractive index?
The light will bend more when entering and leaving if the material has a higher refractive index.
320
The greater the refractive index of a medium, the…?
Lower the speed of light.
321
The lower the refractive index of a medium, the..?
Higher the speed of light.
322
What does Snells Law describe?
The relationship between angle of incidence and refraction.
323
What is the equation for Snells Law?
Sin Theta 1 / Sin Theta 2 = n2 / n1 = v1 / v2
324
What is a Lens?
A lens is an optical device that refracts light.
325
What is a Convex Lens?
A convex or converging lens focuses the light waves.
326
What is a Concave Lens?
A Concave or Divergent Lens is used to spread or diffuse light waves.
327
What do fibre optics deal with?
The transmission of light through fibres.
328
What are the 3 advantages of Fibre Optic transmission?
Lighter and Smaller
Able carry way more info
Intrinsically safer
329
What is the main disadvantage of Fibre Optics?
They are difficult to terminate.
330
How are fibre optics made up?
Fibre Optic cables are made up of:
Core made with a high refractive index material
Cladding made with a low refractive index material.
331
What is Toal Internal Reflection?
TIR is the complete reflection of light at the border betweent two mediums when the light hits the border at an angle greater than the critical angle.
332
What is the Critical Angle?
The critical angle is the angle of incidence where the angle of refraction is 90 degrees.
333
What is Mechanical Wave?
A mechanical wave is the oscillation of material.
334
What is a Transverse Wave?
A Transverse wave is where the displacement of medium is perpendicular to the direction of the wave.
335
What is a Longitudinal Wave?
A Longitudinal Wave is one where the displacement of the medium is parallel to the direction of the wave.
336
What is it called when the particles the wave travels through are close together?
Compression
337
What is it called when the particles the waves travel through are spread apart?
Refraction or Expansion
338
What is the relationship between Periodic Time and Frequency?
They are reciprocals to each other.
339
What is a Standing Wave?
A combination of two waves of the same amplitude and frequency moving in opposite directions.
340
What is the amplitude of the quietest sound a human ear can hear?
20 micro pascals
341
What is the speed of sound in a room?
343 m/s
342
The higher the frequency, the higher or lower is the pitch of the sound?
Higher the pitch
343
The lower the frequency, the higher the or lower the pitch?
The lower the pitch
344
What is the Doppler Effect?
As a source of sound travels towards you the frequency of the sound is higher so the pitch is higher, once the source goes past you, the frequency gets lower and the pitch drops.
345
What are the 4 names of the Otto Cycle Stages?
1-2: Adiabaric Compression
2-3: Reversible Isochoric Heating
3-4: Adiabaric Expansion
4-1: Reversible Isochoric Rejection
346
What medium slows down light the most?
Diamond
347
What does Latent Heat of Fusion refer to?
Solid to Liquid or Liquid to Solid
348
What is an example of a forced vibration?
Aircraft Wheels
B1 Moduels
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