text: /**
   * PhysicsJS v0.7.0 - 2014-12-08
   * A modular, extendable, and easy-to-use physics engine for javascript
   * http://wellcaffeinated.net/PhysicsJS
   *
   * Copyright (c) 2014 Jasper Palfree <jasper@wellcaffeinated.net>
   * Licensed MIT
   */
  (function (root, factory) {
      if (typeof define === 'function' && define.amd) {
          define(['physicsjs'], factory);
      } else if (typeof exports === 'object') {
          module.exports = factory.apply(root, ['physicsjs'].map(require));
      } else {
          factory.call(root, root.Physics);
      }
  }(this, function (Physics) {
      'use strict';
      /** 
       * class ConstantAccelerationBehavior < Behavior
       *
       * `Physics.behavior('constant-acceleration')`.
       *
       * Constant acceleration behavior.
       *
       * Basically the "gravity" behavior. Used to give "earth-like gravity" to the world.
       *
       * Additional options include:
       * - acc: The acceleration vector (Vectorish). (default: `{ x: 0, y: 0.0004 }`)
       **/
      Physics.behavior('constant-acceleration', function( parent ){
      
          var defaults = {
      
              acc: { x : 0, y: 0.0004 }
          };
      
          return {
      
              // extended
              init: function( options ){
      
                  parent.init.call( this );
                  this.options.defaults( defaults );
                  this.options( options );
      
                  // extend options
                  this._acc = new Physics.vector();
                  this.setAcceleration( this.options.acc );
                  delete this.options.acc;
              },
      
              /**
               * ConstantAccelerationBehavior#setAcceleration( acc ) -> this
               * - acc (Vectorish): The acceleration vector
               * 
               * Set the acceleration of the behavior.
               **/
              setAcceleration: function( acc ){
      
                  this._acc.clone( acc );
                  return this;
              },
      
              // extended
              behave: function( data ){
      
                  var bodies = this.getTargets();
      
                  for ( var i = 0, l = bodies.length; i < l; ++i ){
                      
                      bodies[ i ].accelerate( this._acc );
                  }
              }
          };
      });
      // end module: behaviors/constant-acceleration.js
      return Physics;
  }));// UMD