/* Flywheel energy
Copyright 2004 by Dale Heatherington (coded Jan 7, 2004) */

function flywheel(dataform,m,d,rpm,units)
{
	

	if(units[1].checked){ /* convert to metric */
		mass = (m / 16) / 2.204;   /* ounces to kilograms */
		radius = (d/2) * 2.54 / 100; /* inches to meters */
		}
	else{
		mass = m / 1000; 	/* grams to kilograms */
		radius = d/2 / 1000;	/* mm to meters */
		}


	Vsurface = (rpm/60) * 3.142 * 2 * radius;
	V = (rpm/60) * 2 * 3.142;	/* convert RPM to radians per second */
	
	Inertia = .5 * mass * (radius * radius);  /* Moment of inertia for disk */
	KE = 0.5 * Inertia * (V * V);		 /* Kinetic energy for disk */
	cforce = ( 4 * (3.142 * 3.142) * mass * radius) / ((1/(rpm/60)) * ((1/(rpm/60))));
	cforce_pounds = 0.2248 * cforce;

	gforce = ((Vsurface * Vsurface) / radius) / 9.80665 ;

        dataform.ke_disk.value = KE;
        dataform.ke_ring.value = KE * 2;
        /* dataform.cforce.value = cforce; */
	/*  dataform.cforce_kg.value = cforce * 0.1019716; */
        dataform.surface_speed.value = Vsurface;
        dataform.surface_speed_fps.value = Vsurface * 3.2808 ;
	dataform.inertia_disk.value = Inertia;
	dataform.inertia_ring.value = Inertia * 2;
        dataform.gforce.value = gforce;



 }