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71 Cards in this Set
- Front
- Back
Displacement
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Linear distance of the position of an object from a given reference point
Vector (s) |
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Velocity
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Rate of change of displacement
Vector (v or u) |
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Acceleration
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Rate of change of velocity
Vector (a) |
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Speed
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Rate of change of distance
Scalar (v or u) |
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Newton's 1st Law of Motion
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An object remains stationary or at a constant velocity if there is no resultant force acting on the object.
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Condition for translational equilibrium
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There is no resultant force on the object in any direction
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Newton's 2nd Law of Motion
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A resultant force acting on a body equals the rate of change of momentum of the body
Force = mass x acceleration |
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Linear momentum
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Product of mass and velocity
p = mv |
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Impulse
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Product of force and time
Change in momentum ∆p = F x t |
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Law of conservation of Linear Momentum
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If the net external force acting on a system is zero, then the total momentum of the system is constant.
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Newton's 3rd Law of Motion
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When body A exerts a force on body B, body B exerts an equal and opposite force on body A.
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Principle of Conservation of Energy
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The total energy of a closed system is constant.
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Power
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Rate of transforming energy or rate at which work is done.
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Efficiency
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Ratio of useful power of the system to the input power
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Temperature
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Is a measure of how hot or cold an object is. It determines the direction of thermal energy transfer between two objects. It measures the average random kinetic energy of the molecules of an ideal gas.
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Kelvin
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Is the measure of temperature using a scale beginning on absolute zero.
Absolute zero is where the molecules have no kinetic energy and thus no movement. |
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Relationship between Kelvin and Celsius
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K = C +273
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Internal energy
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The total potential energy and random kinetic energy of the molecules of the substance.
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Kinetic energy of molecules
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Arises from the random movement of the molecules.
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Potential energy of the molecules.
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Arises from the forces between molecules
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Mole
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Has as many molecules as there are atoms in 12g of Carbon (12C).
1 mole contains 6.022 x 10^23 atoms |
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Molar mass
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The mass of one mole of substance in grams
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Avogadro's constant
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The number of atoms in 12g of Carbon (12C)
6.022 x 10^23 |
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Specific heat capacity
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The amount of thermal energy required to raise the temperature of one unit mass by one degree
C = Q/m∆T |
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Thermal capacity
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The amount of thermal energy required to raise the temperature of an object by one degree.
C = Q/∆T |
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Specific latent heat
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Thermal energy absorbed or released per unit mass of a substance at a constant temperature during a change of phase.
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Pressure
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Force per unit area
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Assumptions of the kinetic model of an ideal gas
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1) Perfectly elastic
2) Spheres 3) Identical 4) No forces between molecules |
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Thermal equilibrium
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Heat flows from the hot body to the cold body until they are at the same temperature.
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Displacement (SHM)
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Instantaneous distance of the moving object from its mean position (m)
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Frequency
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Number of oscillations completed per unit time (Hz)
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Time Period
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Time taken for 1 complete cycle
T = 1/f |
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Amplitude
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Maximum displacement from the equilibrium position
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Phase Difference
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Difference in phase angle between 2 oscillations with the same frequency.
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Simple Harmonic Motion
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When the acceleration on the body is directed towards equilibrium and is proportional to its displacement from equilibrium.
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Damping
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It involves a force that is always in the opposite direction to the direction of motion of the oscillating particle. The force is a dissipative force, which reduces the total energy of the system.
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Natural frequency
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The frequency at which an object will vibrate if "disturbed"
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Forced oscillations
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If an object is forced to oscillate by a periodic external force (not at its natural frequency), either a very large increase in amplitude is seen or the body vibrates with maximum amplitude.
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Travelling waves
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Progressive/ travelling waves transfer energy and there is no net motion of the medium through which the wave travels.
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Displacement (waves)
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Distance of an oscillating particle in a given direction from its mean.
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Amplitude
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The maximum displacement of a particle from its rest/equilibrium
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Frequency
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Number of oscillations per unit time
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Time Period
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Time for one complete cycle
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Equilibrium position
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Where the particle would rest if not disturbed
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Intensity
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The rate of flow of energy across the cross sectional area perpendicular to the direction of wave propagation.
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Wavelength
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Distance moved by wavefront during one oscillation of the source/ distance between consecutive neighboring crests
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Wavefront
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Are always at 90degrees to the direction of travel of the wave and are separated by wavelength.
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Wave speed
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Rate at which energy is transferred/ distance traveled by a wave front per unit time
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Electromagnetic waves
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All travel at the same speed in free space, 3 x 10^8 m/s
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Snell's Law
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The ratio of the velocities of the waves in two media is equal to the ratio of the sines of the angles of incidence and refraction of the rays.
sin i / sin r = v1 / v2 |
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Refractive Index
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The ratio of the velocity of the wave in two media
Or the ratio of angle of incidence to the angle of refraction |
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Principle of Superposition
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When the paths of two waves of the same type coincide, the resultant displacement is the sum of the 2 individual displacements at that point.
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Constructive Interference
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When two waves meet, the resultant displacement is greater than that of an individual wave.
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Destructive Interference
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When two waves meet, the resultant displacement is less than that of an individual wave.
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Conditions for Constructive Interference
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If two waves of the same type have a path difference of a whole number of wavelengths, nλ, or have a phase difference of 2nπ
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Conditions for Destructive Interference
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Path or Phase difference of:
(n+1/2)λ or (2n+1)π |
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Electric Potential Difference
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Work done per unit charge to move a small positive charge between two points
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Electronvolt, eV
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Work done in moving an electron through a p.d. of 1V
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Current
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Rate of flow of charge
I = Q/T |
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Resistance
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The rate at which a charge can flow through a conductor depends on the resistance (which is dependent on size and material)
R = ρL/A More current flows through a short fat conductor than a long thin one |
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Ohms Law
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The current is proportional to the voltage across it at constant temperature for Ohmic materials.
V = IR |
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Electromotive force, emf
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Total electrical energy supplied by the cell per unit charge as it flows through the cell
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Newton's Universal Law of Gravitation
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Every single point mass attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of their separation.
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Gravitational Field Strength
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Force per unit mass on a small mass placed at the point
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Electric Charge
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There are two types: positive and negative
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Law of Conservation of Charge
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The total charge of a closed system is constant
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Coulomb's Law
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F = kQ/r^2
The force experienced by 2 point charges is directly proportional to the product of their charge and inversely proportional to the square of their separation. |
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Electric Field Strength
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Force per unit charge felt by a positive test charge placed in a field.
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Moving charges
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give rise to magnetic fields:
e.g. Moving charge/ current in a wire creates a magnetic field around the wire. |
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Magnitude of field
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B = FIlsin(angle)
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Direction of field
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From n to S or the direction of force acting on small point north pole of a compass
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