The force of friction between the pavement and the tires
Trial and error
scientific laws and theories are proven by experimental data and large bodies of evidence.
Frequency, f, is how many cycles of an oscillation occur per second and is measured in cycles per second or hertz (Hz). The period of a wave, T, is the amount of time it takes a wave to vibrate one full cycle. These two terms are inversely proportional to each other: f = 1/T and T = 1/f