Year 11 Full Document (VOCABULARY Flashcards)

Vocabulary flashcards covering motion, forces, energy, waves, optics, thermodynamics, and electrostatics from the lecture notes.

Scalar quantity

A quantity with magnitude only and no direction.

Vector quantity

A quantity with both magnitude and direction.

Displacement

The straight line distance from start to end in a given direction; a vector quantity.

Velocity

Rate of change of displacement; speed with direction.

Speed

Rate of motion; magnitude of velocity.

Acceleration

Rate of change of velocity with time (a = Δv/Δt); units m s^-2.

Kinematics

Study of motion without analyzing forces.

SUVAT equations

Set of equations relating displacement, initial and final velocity, acceleration and time for constant acceleration.

v^2 = u^2 + 2as

Final velocity squared equals initial velocity squared plus two times acceleration times displacement.

v = u + at

Final velocity equals initial velocity plus acceleration times time.

s = ut + 1/2 at^2

Displacement equals initial velocity times time plus one half acceleration times time squared.

Net force

Vector sum of all forces acting on an object.

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion unless acted on by a net external force.

Newton's Second Law

The net force acting on an object equals mass times acceleration (F = ma).

Weight

Gravitational force Fg = mg acting downward.

Normal force

Support force exerted by a surface perpendicular to the contact surface.

Friction

Opposes relative motion between surfaces.

Tension

Pull transmitted through a string, rope, or cable.

Gravitational force

Weight; force due to gravity Fg = mg, acting downward.

Electromagnetic force

Force arising from electromagnetic interaction between charges.

Nuclear force

Force within the atomic nucleus.

Equilibrium

Net force is zero; no change in motion.

Static equilibrium

An object at rest with net force zero.

Dynamic equilibrium

An object moving with constant velocity with net force zero.

Work

Energy transferred by a force over a displacement; W = F s cos theta.

Power

Rate of doing work or energy transfer; P = W/Δt.

Kinetic energy

Energy of motion; K = 1/2 m v^2.

Gravitational potential energy

Energy due to height in a gravitational field; U = m g h.

Potential energy

Stored energy due to position; general term for energy that can be transformed.

Conservation of energy

Energy cannot be created or destroyed; it is conserved and transformed.

Wave

A disturbance that transfers energy through space and time.

Mechanical wave

Waves that require a medium to propagate (eg, sound, water waves).

Electromagnetic wave

Waves that do not require a medium (eg, light, radio).

Transverse wave

Particles oscillate perpendicular to the direction of energy transfer.

Longitudinal wave

Particles oscillate parallel to the direction of energy transfer.

Amplitude

Maximum displacement from equilibrium; relates to energy of the wave.

Wavelength

Distance between successive crests or compressions; relates to color and pitch.

Frequency

Number of cycles per second; measured in Hertz (Hz).

Period

Time for one complete cycle; T = 1/f.

Wave velocity

Speed at which a wave travels; v = f λ.

Refraction

Bending of a wave when entering a different medium due to speed change.

Snell's Law

n1 sin θ1 = n2 sin θ2; relates angles and refractive indices.

Refractive index

n = c/v; ratio of light speed in vacuum to speed in medium.

Total internal reflection

All light reflects when moving from a denser to a less dense medium at angles above the critical angle.

Plane mirror

Flat mirror that produces a virtual image of the same size behind the mirror.

Concave mirror

Converging mirror; can produce real or virtual images depending on object distance.

Convex mirror

Diverging mirror; produces virtual, smaller images.

Convex lens

Converging lens; focuses light; can form real or virtual images.

Concave lens

Diverging lens; forms virtual, upright, smaller images.

Mirror equation

1/f = 1/u + 1/v; relates object distance, image distance and focal length.

White light

Combination of all visible wavelengths (roughly 400–700 nm).

Dispersion

Separation of white light into colors due to wavelength dependent refraction.

Intensity

Power per unit area; I = P/A.

Inverse square law

I is proportional to 1/r^2 for point sources.

Decibel

Logarithmic unit for sound intensity; L = 10 log10(I/I0).

Speed of sound

Approximate speed of sound in air around 340 m s^-1 at room temperature.

Doppler effect

Change in observed frequency due to relative motion of source and observer.

Beat frequency

Difference between two close frequencies; fbeats = |f1 - f2|.

Node

Point of zero displacement in a standing wave.

Antinode

Point of maximum displacement in a standing wave.

Fundamental frequency

First harmonic; f0.

Natural frequency

Frequency at which a system tends to oscillate in absence of driving force.

Resonance

Driving frequency equals natural frequency; maximum amplitude.

Period of a pendulum

T = 2π sqrt(L/g); time for one complete swing.

Driving frequency

Frequency of an external forcing function.

Thermodynamics

Study of heat and energy transfer.

Zeroth Law

If two systems are each in thermal equilibrium with a third system, they are in equilibrium with each other.

First Law

Energy cannot be created or destroyed; energy is conserved in isolated systems.

Second Law

Total entropy of interacting systems tends to increase; energy disperses.

Third Law

As temperature approaches absolute zero, entropy approaches a constant minimum.

Specific heat capacity

Amount of heat needed to raise the temperature of a substance by 1 degree; c in Q = m c Δt.

Q = m c Δt

Heat required to change temperature of a mass m by Δt with specific heat c.

Latent heat

Energy required to change phase without changing temperature (fusion, vaporisation).

Conduction

Heat transfer through a material by particle interactions.

Convection

Heat transfer by movement of a fluid.

Radiation

Heat transfer by electromagnetic waves, notably infrared.

Coulomb's law

Force between charges: F = k q1 q2 / r^2; attractive if opposite charges.

ε0

Permittivity of free space; approximately 8.854e-12 F/m.

Charge

Quantity of electricity carried by a particle; measured in Coulombs.