The frequency of a drum note is 20Hz. what does this tell you about the drum skin movement

The drum skin oscillates 20 times per second

Explanation:

The frequency of a note is dependent on the mechanical activities that occur when it is produced. A drum is beaten in this case. The oscillation of the drum skin transfers sound waves to the air particles which move at the same frequency before reaching our ears.

If the frequency of the sound wave is 20 Hz this means that the wave is oscillating 20 times in one second. For the drum to produce such a sound, the skin must have been oscillating at the same frequency of 20 oscillations per second too.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.