What properties of a wave do you need to calculate the wave speed?

The frequency and the wavelength

Explanation:

A wave is a periodic disturbance of the space that carries energy without carrying matter.

The displacement of a wave is described by a sine/cosine function.

Moreover, there exist two types of waves:

- Mechanical waves: they are produced by the oscillations of the particles in a medium - they can only propagate through a medium (not through a vacuum)

- Electromagnetic waves: they consist of the oscillations of the electric and magnetic fields - these are the only waves able to propagate through a vacuum

The speed of a wave is given by:

where:

is the frequency of the wave, which is the number of oscillations completed by the wave per second

is the wavelength of the wave, which is the distance between two consecutive crests (point of maximum amplitude) of the wave

Therefore, if we know wavelength and frequency of a wave, we can calculate its speed.

they are non-matter

explanation:

they are non-matter. basically, any type of energy or any abstract concept is an example of something that does not matter. other examples include dreams, magnetism, radio, and hate