terms

• energy

  The ability to do work
• energy store

  a form of energy
• kinetic energy


  energy which a body possesses by virtue of being in motion
• gravitational potential energy


  energy an object possesses because of its position in a gravitational field
• thermal energy

  the internal energy present in a system due to its temperature
• elastic potential energy


  the energy stored in elastic materials as the result of their stretching or compressing
• emit


  to give off or send out
• absorb

  to take in
• conservation of energy


  The principle that energy cannot be created or destroyed
• closed system


  A system in which energy, but not matter, is exchanged with its surroundings.
• pendulum


  A hanging mass that swings back and forth when pulled to one side and let go.
• work

  (joules, J) Force x Distance, the exertion of force overcoming resistance or producing molecular change
• joules


  the SI unit of work or energy, equal to the work done by a force of one newton when its point of application moves one metre in the direction of action of the force
• force


  (newtons, N) A push or a pull
• Newtons


  the SI unit of force. It is equal to the force that would give a mass of one kilogram an acceleration of one metre per second per second
• kilograms

  the SI unit of mass, equivalent to the international standard kept at Sèvres near Paris
• mass


  (kilograms, kg) the quantity of matter which a body contains
• weight

  (newtons, N) the force exerted on the mass of a body by a gravitational field.
• metres


  (m) a measure of distance or displacement.
• time


  (seconds, s) the indefinite continued progress of existence and events that occur in apparently irreversible succession from the past through the present to the future.
• unit

  standards for measurement of physical quantities that need clear definitions to be useful
• precision


  refers to the closeness of two or more measurements to each other
• accuracy


  the degree of closeness of measurements of a quantity to that quantity's true value.
• friction


  the resistance that one surface or object encounters when moving over another.
• gravitational field strength


  (g) The force per unit mass experienced by a mass placed in a gravitational field.
• speed


  (meters/second, m/s) The distance an object travels per unit of time, Distance / Time
• spring constant


  (k) a parameter that is a measure of a spring's resistance to being compressed or stretched
• useful energy


  Energy converted by a device into the form(s) the device was designed for.
• wasted energy


  Energy converted by a device into the form(s) the device was NOT designed for.
• dissipate


  to spread out and become less concentrated
• efficiency

  The percentage of the input work that is converted to output work. = useful output energy supplied by device (J) / total input energy of the device (J) x 100
• order of magnitude

  estimate of quantity to the nearest power of ten
• power


  (work/time, J/t) the rate of doing work
• Watts


  (W) the SI unit of power, equivalent to one joule per second
• thermal conductivity


  The ability of an object to transfer heat
• conduction


  Form of heat transfer where heat energy is directly transferred through direct contact.
• conductor


  A material that allows heat and electricity to pass through it.
• insulator


  A material that does not allow heat or electrons to move through it easily.
• infrared radiation


  Electromagnetic waves with wavelengths that are longer than visible light but shorter than microwaves; heat radiation
• temperature

  (Celsius, C) A measure of the average kinetic energy of the particles in a sample of matter