// g = (1.226 * radius) / time squared
var g_calc = function() {
    var radius,
    time, g;
    radius = Number(document.skidpad.Radius.value);
    time = Number(document.skidpad.Time.value);
    g = (1.226 * radius) / Math.pow(time,2);
    document.skidpad.g.value = Math.round(g * 100) / 100;
    return g;
};