Cycle per second Cycle per second The cycle per second was a once-common English name for the unit of frequency now known as the hertz (Hz). The plural form was typically used, often written cycles per second, cycles/second, c.p.s., c/s, ~, or, ambiguously, just cycles. The term comes from the fact that sound waves have a frequency measurable in their number of oscillations, or "cycles", per second. With the organization of the International System of Units in 1960, the cycle per second was officially replaced by the hertz, or reciprocal second, "s" or "1/s". Symbolically, "cycle per second" units are "cycle/second", while hertz
Kinetic theory of gases can calculate the number of atomic or molecular collisions with a wall of a container per unit area per unit time. Assuming an ideal gas, a derivation results in an equation for total number of collisions per unit time per area: This quantity is also known as the "impingement rate" in vacuum physics. From the kinetic energy formula it can be shown that where "v" is in m/s, "T" is in kelvins, and "m" is the mass of one molecule of gas. The most probable (or mode) speed formula_26 is 81.6% of the rms speed formula_27, and the mean (arithmetic