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a natural event that involves a change in the position or location of something


distance traveled per unit time

average speed

a rate of motion determined by dividing the total distance traveled by the total travel time

instantaneous speed

The speed at any given point in time


Speed in a given direction.


the steepness of a line on a graph, equal to its vertical change divided by its horizontal change

plate tectonics

the study of large scale movement and deformation of the earth's outer layers in terms of rigid plates over a partly molten layer of the upper mantle


The rate at which velocity changes


a push or pull exerted on an object

Net Force

The overall force on an object when all the individual forces acting on it are added together


the force that opposes the motion of one surface as it moves across another surface


the force that pulls objects toward each other


a body of matter without definite shape


the vertical force exerted by a mass as a result of gravity

Free Fall

the motion of a falling object when the only force acting on it is gravity

Terminal velocity

the constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity


an object thrown into the air with great force


the tendency of an object to resist a change in motion


the product of a body's mass and its velocity

conservation of momentum

Momentum of a system remains constant when there are no net external forces acting on it.


any celestial body orbiting around a planet or star

centripetal force

any force that causes an object to move in a circular path


the force applied to a unit area of surface


a continuous amorphous substance that tends to flow and to conform to the outline of its container: a liquid or a gas

buoyant force

upward force exerted on an object immersed in a fluid


mass divided by volume

Archimedes principle

the buoyant force on an object is equal to the weight of the fluid displaced by the object

Hydraulic system

a system that multiplies force by transmitting pressure from a small surface area through a confined fluid to a larger surface area


Force x Distance


(physics) the rate of doing work


any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks

Mechanical advantage

the number of times that a machine increases an input force

efficiency of machines

A comparison of the output work to the input work


The capacity to do work or to produce heat

Kinetic energy

the energy of motion

potential energy

the energy that an object has because of the position, shape, or condition of the object

types of energy

radiant energy, chemical energy, mechanical energy, electrical and thermal energy, nuclear energy


that which has mass and occupies space

fossil fuel

a nonrenewable energy resource formed from the remains of organisms that lived long ago; examples include oil, coal, and natural gas


a process in which a substance reacts with oxygen to give heat and light


A measure of the average energy of motion of the particles of a substance

absolute zero

The coldest temperature, 0 Kelvin, that can be reached. It is the hypothetical temperature at which all molecular motion stops.


the movement of thermal energy from a substance at a higher temperature to one at a lower temperature

specific heat

the amount of heat required to raise the temperature of 1g of a substance 1 degree Celsius


the direct transfer of heat from one substance to another substance that it is touching


the transfer of heat by the movement of currents within a fluid


the transfer of energy by electromagnetic waves


a device designed to transmit electricity, heat, etc.


a material that does not allow heat or electrons to move through it easily.

change of state

The conversion of a substance from one physical form to another

thermal expansion

The increase in volume of a substance due to an increase in temperature


motor that converts thermal energy to mechanical work


a device that uses outside energy source to transfer thermal energy from a cool area to a warm area


(physics) a device that attracts iron and produces a magnetic field

magnetic pole

one of the two ends of a magnet where the magnetism seems to be concentrated

magnetic field lines

Invisible lines that map out the magnetic field around a magnet


smallest particle of an element


an instrument for showing directions, consisting of a needle or compass card that points to the north magnetic pole, which is near the North Pole.

Solar Wind

continuous stream of high-energy particles released into space in all direction from the sun's corona

Electric field

the region around a charged object where the object's electric force interacts with other charged objects

electric current

the continuous flow of electric charges through a material

electric circuit

a complete, unbroken path through which electric charges can flow


a substance that readily conducts e.g. electricity and heat


a material through which electric current DOES NOT pass easily


the difference in electrical charge between two points in a circuit expressed in volts


an electrical device that resists the flow of electrical current


A source of stored chemical energy for electric currents, having a positive (+) and a negative (-) terminal.

series circuit

a circuit in which all parts are connected in a single loop

parallel circuit

a closed electrical circuit in which the current is divided into two or more paths and then returns via a common path to complete the circuit


a device used to measure current in a circuit


a device used to measure voltage, or electrical potential energy difference

Electrical power

the product of voltage and current

short circuit

a connection that allows current to take an unintended path


electrical device that can interrupt the flow of electrical current when it is overloaded

circuit breaker

a device that trips like a switch and opens the circuit when overloaded

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