text: class PendulumParticle extends Particle{
  
      constructor(position, physX = new PhysX(), color, width, length, radius) {
          super(position, physX, color);
          this._width = width;
          this._length = length;
          this._radius = radius;
          return this;
      }
  
      get width() {
          return this._width;
      }
  
      set width(value) {
          this._width = value;
          return this;
      }
  
      get length() {
          return this._length;
      }
  
      set length(value) {
          this._length = value;
          return this;
      }
  
      get radius() {
          return this._radius;
      }
  
      set radius(value) {
          this._radius = value;
          return this;
      }
  
      updateAngularAcceleration(){
          this.angularAcceleration = - world.gravityConstant * this.physX.mass * Math.sin(KeglerMaths.radians(this.angle)) * 0.001;
          return this;
      }
  
  
  
      drawSpecific(ctx) {
  
          ctx.fillRect(  - (this.width / 2),
                          0,
                          this.width,
                          this.length
                      );
          ctx.beginPath();
          ctx.arc(0,
                  this.length,
                  this.radius,
                  0, 2 * Math.PI, true);
  
          return this;
      }
  
  
  }