the following quotes are from
https://sites.google.com/site/technicalarchery/homeKinetic Energy - The energy transferred from the bow to the arrow upon release.
The kinetic energy (KE) of an arrow can be obtained by weighing the arrow with a scale and observing the speed with a chrono, and applying some math.
Potential Energy - The energy stored in the bow at any draw distance. Potential energy is a function of draw force and draw distance.
The Potential Energy of a drawn bow can be obtained by counting squares under a plotted force draw curve or calculating the area.
Should you wish to know how well your bow performs, one can compare potential energy of the bow to the kinetic energy of the arrow. Looking at the equation below, we see our differences or losses broken down and categorized into hysteresis (elasticity efficiency) and energy used move limb mass back to brace height. I should also add that the "Kinetic Energy of the Bow" also includes the string.
Potential Energy of the Bow = Bow Hysteresis + Kinetic Energy of the Bow + Kinetic Energy of the Arrow
On one side of the pond, imperial units are used to describe energy in foot/pounds, while on the other, energy is stated in SI units of Joules. We could also describe hysteresis and limb energy with foot pounds or joules, should we wish.
In the archery world, we like to compare our observed arrow to an imaginary arrow that has the same energy as the bow, and have invented a unit of measure called virtual mass. It is stated in arrow weight. It is the difference in arrow weight,
at the same velocity as our actual arrow, that when added to the observed arrow weight, gives the bow and the arrow the same energy. It represents the losses in the bow/string, and is considered to be a unit of measure for bows.
Can this invented unit of measure accurately describe bow/string energy losses?
Can this invented unit of measure accurately describe hysteresis losses?
Can it tell the difference between the two?