Waves
Waves are defined as a disturbance in a medium. They transfer both energy and momentum but do not transfer any of the medium.
1. Frequency (f): The amount of round trips that occur in 1 second. It is inversely proportional to period.
2. Period (T): How long it takes for 1 round trip to occur. It is inversely proportional to frequency.
3. Amplitude (A): The max displacement from equilibrium. This quantity does NOT depend on frequency, period, or velocity. Amplitude is determined by how much energy is put into the system!
As you can see in the transverse wave. The movement (propagation) of the wave is perpendicular to the oscillations. In longitudinal waves, the movement is parallel to the oscillations.
An extremely important and well recognized equation is (λ)(f) = v where λ is the wavelength, f is the frequency, and v is the velocity. Another important equation is v =sqr(tension/linear density). This equation shows that velocity is actually an intrinsic property that depends on the medium and NOT on the frequency and wavelength. Now going back to the original equation, (λ)(f) = v, since v is constant, a change in (λ) or (f) will cause a change in the other.
You cause these equations to solve for distance or time. Since v=d/t, t =d/v, t = d/(λ)(f) or dT/(λ) = t. Solving for d, t(λ)/T = d or t(λ)(f) = d
Two Rules
1. When the medium changes, the velocity will change but the frequency will not. This means that velocity is directly proportional to wavelength.
2. When the medium is constant, wave speed does not depend on frequency or wavelength. It depends on the medium. More tension in a rope will lead to a higher speed. A lower density will also lead to a higher wave speed.
