W

Wave
A system with many parts in periodic, or repetitive, motion. The oscillations in one part cause vibrations in nearby parts.
Wave speed
The speed at which a wave crest or trough propagates. Note that this is not the speed at which the actual medium (like the stretched string or the air particles) moves.
Wavelength
The distance between successive wave crests, or troughs. Wavelength is measured in meters and is related to frequency and wave speed by = v/f.
Weak nuclear force
The force involved in beta decay that changes a proton to a neutron and releases an electron and a neutrino.
Weber
The unit of magnetic flux, equal to one T · m2.
Weight
The gravitational force exerted on a given mass.
Weightlessness
The experience of being in free fall. If you are in a satellite, elevator, or other free-falling object, then you have a weight of zero Newtons relative to that object.
Work
Done when energy is transferred by a force. The work done by a force F in displacing an object by s is W = F · s.
Work function
The amount of energy that metal must absorb before it can release a photoelectron from the metal.
Work-energy theorem
States that the net work done on an object is equal to the object’s change in kinetic energy.