Farruca is a form and style of flamenco music. It may be performed with lyrics ( vocals) and as most flamenco styles in can also be danced to. It is played in 4/4, interpreted at a relative slow tempo and accompanied by melody and harmony defining a minor key.
In the following examples you will see how slow tempos are appropriate for “accelerandos” as a possible method of achieving intensity in the dance and impact on the audience.
It is very common in flamenco to relate styles to certain keys. All styles in theory can be played in all keys . Those keys that allow open strings on the guitar broaden the possibility of expression, rhythm and accompaniment of the spanish guitarist. Please follow the link above to read more on the subject