Physics Exam Terminology (SPH4U)

Scalar

Quantity that has only magnitude.

Vector

Quantity with both magnitude and direction.

Position (𝑥⃗)

Distance and direction of an object from a reference point.

Distance (𝑑)

Scalar quantity that refers to the length of the path traveled by an object.

Speed (𝑣)

Scalar quantity representing the distance an object travels per unit of time.

Displacement (𝑑⃗)

Vector quantity that refers to the overall change in an object’s position.

Velocity (𝑣⃗)

Vector quantity representing the change in position of an object over a time interval.

Instantaneous Velocity

The rate of change of an object’s position at a given time.

Terminal Velocity

The maximum velocity attainable by a falling object (drag force = gravitational force).

Acceleration (𝑎⃗)

Change in velocity of an object over a time interval.

Relative Motion

Motion of an object as observed from another object’s frame of reference.

Uniform Motion

Motion at a constant velocity (no change in speed or direction).

Absolute Uncertainty

The fixed amount of error in a measurement.

Relative Uncertainty

The error in a measurement expressed as a percentage of the measured value.

Force (𝐹⃗)

A push or pull (contact or no contact).

Applied Force (𝐹⃗_app)

General term for any contact force.

Tension (𝐹⃗_T)

Force exerted by strings or cables attached to an object.

Friction (𝐹⃗_f)

Force that opposes any real or attempted motion between objects in contact.

Static Friction (𝐹⃗_sf)

Force that prevents a stationary object from starting to move.

Kinetic Friction (𝐹⃗_kf)

Force that acts against the motion of a moving object.

Air Resistance (𝐹⃗_air)

Frictional force that opposes an object’s motion through air.

Normal Force (𝐹⃗_N)

Force that acts to keep objects apart, perpendicular to the surface.

Gravity (𝐹⃗_g)

Force of attraction between all objects with mass.

Net Force (Σ𝐹⃗)

Sum of all forces acting on an object.

Mass

Amount of matter in an object, measured in kilograms (kg).

Weight

Force of gravity exerted on an object, measured in newtons (N).

Inertia

Property of matter that causes it to resist changes to its motion.

Newton's 1^st Law

Object is at rest or has uniform motion unless acted upon by an unbalanced force.

Newton's 2^nd Law

The acceleration of an object is proportional to net force but inversely proportional to mass.

Newton's 3^rd Law

For every action force, there is a reaction force equal in magnitude but opposite in direction.

Coefficient of Friction (𝜇)

Value that measures the slipperiness/roughness of a surface.

Centripetal Force (𝐹⃗_c)

Force that causes an object to move in a circular path, always directed to the center of the curve and perpendicular to the object’s motion.

Centrifugal Force

Apparent outward force experienced by a mass in a rotating frame of reference.

Fictitious Force

A perceived force with no physical origin, used to describe motion in non-inertial frames of reference.

Inertial Frame of Reference

A reference frame where the law of inertia holds true.

Non-Inertial Frame of Reference

A reference frame where the law of inertia does not apply.

Law of Universal Gravitation

Every mass attracts every other mass with a force that is proportional to the product of their masses, and inversely proportional to the square of the distance between centers.

Satellite

An object that orbits a larger object due to gravitational attraction.

Space Station

An artificial satellite (spacecraft) designed for people to live and work in space.

Uniform Circular Motion

Motion at a constant speed along a circular path, where velocity changes direction, and the radius remains constant.

Energy (∆𝐸)

The ability to do work, measured in joules (J).

Law of Conservation of Energy

Energy cannot be created or destroyed, only converted from one form of energy to another.

Work (𝑊)

The transfer of energy to or from an object via the application of force along a displacement.

Work-Energy Theorem

The total work done by all forces on an object equals the object’s change in kinetic energy.

Kinetic Energy (𝐸_k)

Energy an object has due to its motion.

Thermal Energy (𝐸_th)

Energy produced by moving atoms and molecules in an object, often due to friction.

Gravitational Potential Energy (𝐸_g)

Potential energy an object has due to its position in a gravitational field.

Elastic Potential Energy (𝐸_s)

Potential energy stored in stretched, compressed, bent, or twisted elastic objects.

Spring Force (𝐹⃗_s)

Force exerted by an elastic device when stretched or compressed.

Hooke's Law

The stretch or compression of an elastic device is directly proportional to the applied force.

Simple Harmonic Motion

Periodic vibratory motion where the force and acceleration are directly proportional to the displacement.

Damped Harmonic Motion

Repeated motion where amplitude and energy decrease over time.

Momentum (𝑝⃗)

Vector quantity that represents an object’s motion, equal to the product of its mass and velocity.

Law of Conservation of Momentum

During an interaction between two objects with no net external force, the change in momentum of one object is equal in magnitude but opposite in direction to the change in momentum of the other.

Impulse

The change in an object’s momentum, caused by a force applied over a time interval.

Elastic Collision

Collision where the total kinetic energy of the objects is conserved.

Inelastic Collision

Collision where some of the objects’ kinetic energy is lost and converted into other forms of energy.

Completely Inelastic Collision

Collision where the maximum amount of kinetic energy is lost, and the objects stick together after impact.

Wave

Disturbance that transmits energy through a medium.

Wavelength (𝜆)

Distance between two consecutive crests or troughs of a wave.

Frequency (𝑓)

Number of wave cycles that pass a point in one second, measured in hertz (Hz).

Period (𝑇)

Time taken for one complete wave cycle.

Reflection

The bouncing of light off a surface it cannot pass through.

Refraction

The bending of light as it moves from one medium to another.

Index of Refraction (𝑛)

Value that measures how much a wave slows down in a medium.

Diffraction

The spreading of waves as they pass around obstacles or through narrow openings.

Resolution

The ability of a lens to produce sharp, separate images of closely spaced objects.

Constructive Interference

Occurs when waves combine to produce a waveform with an increased amplitude.

Destructive Interference

Occurs when waves combine to produce a waveform with a decreased amplitude.

Node

Point of destructive interference with minimum amplitude (dark fringe).

Antinode

Point of constructive interference with maximum amplitude (bright fringe).

Radiation

The emission or transmission of energy in waves.

Electromagnetic Spectrum

The full range of electromagnetic radiation, organized by frequency or wavelength.

Radiowave

Electromagnetic waves with the longest wavelength, used in communication systems (ex. TV, radio, remote controls).

Microwave

Electromagnetic waves with shorter wavelengths than radiowaves, used in cooking, radar, and cellular devices.

Infrared

Electromagnetic waves with longer wavelengths than visible light, used in thermal imaging and heating.

Visible Light

Electromagnetic waves detectable by the human eye, allowing for vision and colour perception.

Ultraviolet

Electromagnetic waves with shorter wavelengths than visible light, used in sterilization and vitamin D production.

X-ray

High-energy electromagnetic waves used in medical imaging and security scanning.

Gamma Ray

Electromagnetic waves with the shortest wavelengths and highest energy, emitted during nuclear reactions.

Laser

A device that produces a focused beam of light at a single wavelength.

Special Relativity

Einstein’s theory stating that the laws of physics are valid in all inertial frames of reference, and the speed of light in a vacuum (c = 3.00 × 10⁸ m/s) is constant in every inertial frame.

General Relativity

Einstein’s theory explaining that the gravitational effects between masses result from their warping of spacetime.

Time Dilation

The slowing down of time in a system as observed by an observer moving relative to the system.

Length Contraction

The shortening of an object’s measured length due to its motion relative to an observer.

Proper Time (∆𝑡₀)

Time interval measured by an observer at rest with respect to the event.

Proper Length (𝐿₀)

Length of an object measured by an observer at rest with respect to the object.

Rest Mass

Mass of a particle at rest.

Rest Energy

Energy associated with a particle’s rest mass.

Conservation of Mass-Energy

Mass and energy are equivalent, and the total amount of mass and energy in a closed system remains constant.

Particle

Small, localized object with properties of mass, charge, and energy.