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The distance that an object travels per unit of time

Average Speed

Calculated by dividing the total distance traveled by the total time of travel


The distance AND direction of an object's position from the starting point


Includes the speed of an object and its direction of motion.


Occurs when an object changes its speed, its direction, or both


The tendency of an object to resist any change in motion


A push or pull that one body exerts on another

Balanced Forces

Forces on a body that are equal in size and opposite in direction.

Instantaneous Speed

The speed at any given point in time


A force that opposes motion between two touching surfaces


The gravitational force exerted on an object


The product of the mass of an object and its velocity

Static Friction

Exists between two surfaces that are not moving past each other


Two masses exert an attractive force on each other

Chemical Potential Energy

Energy stored in the chemical bonds between atoms

Gravitational Potential Energy

Depends on the mass of the object, its height above ground and its acceleration due to gravity


The SI unit of energy

Kinetic Energy

Energy in the form of motion

Mechanical Energy

Is the sum of the potential and kinetic energy in a system

Elastic Potential Energy

Energy stored by something that can stretch or compress

Resistance Force

Opposing the effort force

Modified Inclined Plane

Wedge, screw

Effort Force

The force applied to a machine

Wheel and Axle

Gears are a modified form of this simple machine

Simple Machine

A machine that does work with only one movement

Inclined Plane

The wedge and screw are modified forms of this machine


W(out) / W(in) X 100


A bar that is free to pivot, or turn, around a fixed point


This is accomplished when a force acts through a distance


A device that makes doing work easier

Mechanical Advantage

The number of times a machine multiplies the effort force


Moves from areas of hot to areas of cold


The transfer of energy in a fluid by the movement of heated particles


Heat transfer by touch


Charging a material by bringing it close to a charged object

Closed Circuit

An electrical circuit that has only one way to flow

Heat Conductor

Allows for the easy flow of electrons

Heat Engine

A device that converts heat energy into mechanical energy


A measure of the average kinetic energy of the particles in a material

Heat Mover

Air conditioner is an example

Solar Energy

Energy from the sun

Specific Heat

Water has a value of 4184[J/(kg K)]


Transfer of energy by electromagnetic waves


Transfer of thermal energy by direct contact of particles

Thermal Energy

Sum of the kinetic and potential energy of all of the molecules in an object.

Electric Current

Produce by the flow of electrons through a material


A material that does NOT allow electrons to easily flow through it


Tendency of a material to oppose the flow of electrons through it

Parallel Circuit

A type of circuit that has mor than one branch for current to flow


Equals current X voltage difference


The "push" that causes charges to move in a circuit

Series Circuit

A circuit with only one path


Can be used to increase or decrease the voltage in an AC

Electrical Generator

Converts mechanical energy into electrical energy


A large wheel that rotates when pushed by water, wind or steam


Region where the magnetic force of a magnet is strongest

Direct Current

Batteries produce this type of electron flow


Device that uses an electromagnet to measure electric current

Electromagnetic Induction

A generation works based on this principle

Alternating Current

Reverses direction of current flow in a regular way


Made of a soft iron core surrounded by loops of current-carrying wire

Fossil Fuel

Examples include coal, petroleum and natural gas


Cured oil that is highly flammable and is formed by decayed organisms

Photovoltaic Cell

Converts light energy into electricity


Energy source that cannot be replace as fast as it is used


Examples include organic matter such as wood and rice hulls

Nuclear Waste

Radioactive by-product resulting from the use of radioactive sources

Geothermal Energy

Thermal energy from the earth that can be used to generate electricity


Electrical energy produced from the energy of moving water

Constructive Interference

When two or more waves overlap and combine to form a new wave


The bending of a wave as it changes speed when passing from one medium to another


Measured from crest to crest or trough to trough on a transverse wave


Matter that waves travel through


Matter moves back and forth at right angles to the direction the wave travels

Longitudinal or Compressional

An example of this type of wave is sound


The number of wavelengths that pass a given point each second


The less dense region of a compressional wave


Relates directly to the energy carried by a wave


Uses reflected underwater sound waves to detect objects


Units used to measure the intensity of a sound

Doppler Effect

Change in pitch or wave frequency due to a moving wave source


The study of sound


Sound waves above the normal frequency range of human hearing


Part of ear that converts sound waves into nerve impulses


Hollow chamber filled with air that amplifies vibrating sound waves


The portion of the electromagnetic spectrum that you can see


Type of energy used to produce thermograms


The ozone layer above the Earth blocks much of this radiation


Particles whose energy is dependent on the frequency of the light


Often used in medicine to produce images of the human body

Electromagnetic Spectrum

Composed of vibrating electrical and magnetic fields.


Very high energy, short wavelength wave that can damage cells


Short waves often used in communications

Coherent Light

Light of only one wavelength that travels with its crests and troughs aligned


Allows some light to pass through, but you cannot see clearly through it


Produced when objects become so hot that they give off light


Does not allow any light to pass through it


Colored material that absorbs some colors and reflects others

Concave or Diverging

Lens that is thinner in the middle than at the edges


Flat, smooth surface that reflects and image

Focal Length

Distance from center of lens or mirror to the point of focus


Transparent outer covering of the eye

Real Image

Formed when light rays converge to form an image

Optical Axis

Imaginary line drawn perpendicular to the surface of a mirror or lens at its center


Part of the eye that converts light images into electrical signals

Convex or Converging

Lens that is thicker in the middle than on the edges

Convex Mirror

Reflects an image that is virtual, upright, and smaller than the object

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