001/*
002 * JScience - Java(TM) Tools and Libraries for the Advancement of Sciences.
003 * Copyright (C) 2006 - JScience (http://jscience.org/)
004 * All rights reserved.
005 * 
006 * Permission to use, copy, modify, and distribute this software is
007 * freely granted, provided that this notice is preserved.
008 */
009package javax.measure.quantity;
010import javax.measure.unit.ProductUnit;
011import javax.measure.unit.SI;
012import javax.measure.unit.Unit;
013
014/**
015 * This interface represents the moment of a force. The system unit for this
016 * quantity is "N·m" (Newton-Meter).
017 * 
018 * <p> Note: The Newton-metre ("N·m") is also a way of exressing a Joule (unit
019 *     of energy). However, torque is not energy. So, to avoid confusion, we
020 *     will use the units "N·m" for torque and not "J". This distinction occurs
021 *     due to the scalar nature of energy and the vector nature of torque.</p>
022 * 
023 * @author  <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
024 * @version 1.0, January 14, 2006
025 */
026public interface Torque extends Quantity {
027
028    /**
029     * Holds the SI unit (Système International d'Unités) for this quantity.
030     */
031    public final static Unit<Torque> UNIT = 
032        new ProductUnit<Torque>(SI.NEWTON.times(SI.METRE));
033
034}