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/*
 * Copyright (c) 2010 William Bittle  http://www.dyn4j.org/
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, are permitted 
 * provided that the following conditions are met:
 * 
 *   * Redistributions of source code must retain the above copyright notice, this list of conditions 
 *     and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice, this list of conditions 
 *     and the following disclaimer in the documentation and/or other materials provided with the 
 *     distribution.
 *   * Neither the name of dyn4j nor the names of its contributors may be used to endorse or 
 *     promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR 
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.dyn4j.game2d;

/**
 * Class used to convert units.
 * <p>
 * Dyn4j by default uses meters-kilograms-seconds (MKS) units.  This class can be used
 * to convert to and from MKS.
 * @author William Bittle
 * @version 1.0.3
 * @since 1.0.0
 */
public class UnitConversion {
  /** 1 foot = {@value #FOOT_TO_METER} meters */
  public static final double FOOT_TO_METER = 0.0254 * 12.0;
  
  /** 1 meter = {@value #METER_TO_FOOT} feet */
  public static final double METER_TO_FOOT = 1.0 / FOOT_TO_METER;
  
  /** 1 slug = {@value #SLUG_TO_KILOGRAM} kilograms */
  public static final double SLUG_TO_KILOGRAM = 14.5939029;
  
  /** 1 kilogram = {@value #KILOGRAM_TO_SLUG} slugs */
  public static final double KILOGRAM_TO_SLUG = 1.0 / SLUG_TO_KILOGRAM;
  
  /** 1 pound-mass = {@value #POUND_TO_KILOGRAM} kilograms */
  public static final double POUND_TO_KILOGRAM = 0.45359237;
  
  /** 1 kilogram = {@value #KILOGRAM_TO_POUND} pounds */
  public static final double KILOGRAM_TO_POUND = 1.0 / POUND_TO_KILOGRAM;
  
  /** 1 pound-force = {@value #POUND_TO_NEWTON} newtons */
  public static final double POUND_TO_NEWTON = 4.448222;
  
  /** 1 newton = {@value #NEWTON_TO_POUND} pound-force */
  public static final double NEWTON_TO_POUND = 1.0 / POUND_TO_NEWTON;
  
  /** 1 foot-pound = {@value #FOOT_POUND_TO_NEWTON_METER} newton-meters */
  public static final double FOOT_POUND_TO_NEWTON_METER = 0.7375621;
  
  /** 1 newton-meter = {@value #NEWTON_METER_TO_FOOT_POUND} foot-pounds */
  public static final double NEWTON_METER_TO_FOOT_POUND = 1.0 / FOOT_POUND_TO_NEWTON_METER;
  
  // FPS (mixture of Gravitational and Engineering approaches) to MKS
  
  // Length Conversions
  
  /**
   * Converts feet to meters.
   * @param feet the length value in feet
   * @return double the length value in meters
   */
  public static final double feetToMeters(double feet) {
    return feet * FOOT_TO_METER;
  }
  
  // Mass Conversions
  
  /**
   * Converts slugs to kilograms.
   * @param slugs the mass value in slugs
   * @return double the mass value in kilograms
   */
  public static final double slugsToKilograms(double slugs) {
    return slugs * SLUG_TO_KILOGRAM;
  }
  
  /**
   * Converts pound-mass to kilograms.
   * @param pound the mass value in pound-masses
   * @return double the mass value in kilograms
   */
  public static final double poundsToKilograms(double pound) {
    return pound * POUND_TO_KILOGRAM;
  }
  
  // Velocity Conversions
  
  /**
   * Converts feet per second to meters per second.
   * @param feetPerSecond the velocity in feet per second
   * @return double the velocity in meters per second
   */
  public static final double feetPerSecondToMetersPerSecond(double feetPerSecond) {
    return feetPerSecond * METER_TO_FOOT;
  }
  
  // Force Conversions
  
  /**
   * Converts pound-force to newtons.
   * @param pound the force value in pound-force
   * @return double the force value in newtons
   */
  public static final double poundsToNewtons(double pound) {
    return pound * POUND_TO_NEWTON;
  }
  
  // Torque Conversions
  
  /**
   * Converts foot-pounds to newton-meters.
   * @param footPound the torque value in foot-pounds
   * @return double the torque value in newton-meters
   */
  public static final double footPoundsToNewtonMeters(double footPound) {
    return footPound * FOOT_POUND_TO_NEWTON_METER;
  }
  
  // MKS to FPS (mixture of Gravitational and Engineering approaches)
  
  // Length Conversions
  
  /**
   * Converts meters to feet.
   * @param meters the length value in meters
   * @return double the length value in feet
   */
  public static final double metersToFeet(double meters) {
    return meters * METER_TO_FOOT;
  }
  
  // Mass Conversions
  
  /**
   * Converts kilograms to slugs.
   * @param kilograms the mass value in kilograms
   * @return double the mass value in slugs
   */
  public static final double kilogramsToSlugs(double kilograms) {
    return kilograms * KILOGRAM_TO_SLUG;
  }
  
  /**
   * Converts kilograms to pound-mass.
   * @param kilograms the mass value in kilograms
   * @return double the mass value in pound-masses
   */
  public static final double kilogramsToPounds(double kilograms) {
    return kilograms * KILOGRAM_TO_POUND;
  }

  // Velocity Conversions
  
  /**
   * Converts meters per second to feet per second.
   * @param metersPerSecond the velocity in meters per second
   * @return double the velocity in feet per second
   */
  public static final double metersPerSecondToFeetPerSecond(double metersPerSecond) {
    return metersPerSecond * FOOT_TO_METER;
  }
  
  // Force Conversions
  
  /**
   * Converts newtons to pound-force.
   * @param newtons the force value in newtons
   * @return double the force value in pound-force
   */
  public static final double newtonsToPounds(double newtons) {
    return newtons * NEWTON_TO_POUND;
  }
  
  // Torque Conversions
  
  /**
   * Converts newton-meters to foot-pounds.
   * @param newtonMeters the torque value in newton-meters
   * @return double the torque value in foot-pounds
   */
  public static final double newtonMetersToFootPounds(double newtonMeters) {
    return newtonMeters * NEWTON_METER_TO_FOOT_POUND;
  }
}
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