momentum

u.momentum = function (current, start, time, lowerMargin, wrapperSize, deceleration) {
        var distance = current - start,
            speed = Math.abs(distance) / time,
            destination,
            duration;
        deceleration = deceleration === undefined ? 0.0006 : deceleration;

        destination = current + ( speed * speed ) / ( 2 * deceleration ) * ( distance < 0 ? -1 : 1 );
        duration = speed / deceleration;

        if ( destination < lowerMargin ) {
            destination = wrapperSize ? lowerMargin - ( wrapperSize / 2.5 * ( speed / 8 ) ) : lowerMargin;
            distance = Math.abs(destination - current);
            duration = distance / speed;
        } else if ( destination > 0 ) {
            destination = wrapperSize ? wrapperSize / 2.5 * ( speed / 8 ) : 0;
            distance = Math.abs(current) + destination;
            duration = distance / speed;
        }
        return {
            destination: Math.round(destination),
            duration: duration
        };
    };