Oscillates: vibrates back and forth over the same path, each taking the same amount of time this motion is periodic. Equilibrium position: position in which no force is exerted on mass, at its natural length. Displacement: distance of the mass from equilibrium point at any moment. Cycle: complete to and fro motion from initial point back to same point. Simple pendulum: small object suspended from end of lightweight cord. Period and frequency does not depend on mass. Continuous(periodic) wave: it"s source a disturbance that is continuous and oscillating, source is a vibration or oscillation. Amplitude: max height of a crest (max displacement) Wavelength: distance between two successive crests or two identical points of the wave. Frequency: number of crests or complete cycles that pass per given time. Period: time elapsed between two successive crests passing same point in space. Wave speed: speed at which the wave crests move forward.
