Adjusted line lengths, see #86

js/faradays-law/model/Coil.js

@@ -78,7 +78,8 @@ define( function( require ) {
 
       var sign = this.magnet.flippedProperty.value ? -1 : 1;
 
-      var rSquared = this.position.distanceSquared( this.magnet.positionProperty.get() ) / (NEAR_FIELD_RADIUS * NEAR_FIELD_RADIUS);  // normalized squared distance from coil to magnet
+      var rSquared = this.position.distanceSquared( this.magnet.positionProperty.get() ) /
+                     (NEAR_FIELD_RADIUS * NEAR_FIELD_RADIUS);  // normalized squared distance from coil to magnet
 
       // if magnet is very close to coil, then B field is at max value;
       if ( rSquared < 1 ) {
@@ -109,7 +110,8 @@ define( function( require ) {
       var numberOfCoils = this.numberOfSpirals / 2;
 
       // emf = (nbr coils)*(change in B)/(change in t)
-      this.emfProperty.set( numberOfCoils * (this.magneticFieldProperty.get() - this.previousMagneticFieldProperty.get()) / dt );
+      var changeInMagneticField = this.magneticFieldProperty.get() - this.previousMagneticFieldProperty.get();
+      this.emfProperty.set( numberOfCoils * changeInMagneticField / dt );
       this.previousMagneticFieldProperty.set( this.magneticFieldProperty.get() );
     }
   } );

js/faradays-law/model/FaradaysLawModel.js

@@ -124,12 +124,14 @@ define( function( require ) {
      * @public
      */
     moveMagnetToPosition: function( position ) {
+
+      // TODO: why do we subtract 1 from each of these dimensions?
       var magnetBounds = new Bounds2(
         Math.min( position.x, this.magnet.positionProperty.get().x ),
         Math.min( position.y, this.magnet.positionProperty.get().y ),
         Math.max( position.x, this.magnet.positionProperty.get().x ),
         Math.max( position.y, this.magnet.positionProperty.get().y )
-      ).dilatedXY( this.magnet.width / 2 - 1, this.magnet.height / 2 - 1 );  // TODO: why do we subtract 1 from each of these dimensions?
+      ).dilatedXY( this.magnet.width / 2 - 1, this.magnet.height / 2 - 1 );
 
       // check intersection with any restricted areas if not intersected yet
       if ( this.intersectedBounds === null ) {

js/faradays-law/model/Voltmeter.js

@@ -35,7 +35,7 @@ define( function( require ) {
     // @private {number} - rad/s^2
     this.needleAngularAcceleration = 0;
 
-    // @public {NumberProperty} Needle angle in radians. This drives both the needle location and the light bulb brightness.
+    // @public {NumberProperty} Needle angle in radians. This drives the needle location and the light bulb brightness.
     this.needleAngleProperty = new NumberProperty( 0, {
       tandem: tandem.createTandem( 'needleAngleProperty' ),
       units: 'radians',

js/faradays-law/view/BulbNode.js

@@ -51,7 +51,9 @@ define( function( require ) {
     // center of both.  This was the easiest to work with.
 
     // Create the bulb body.
-    var bulbShape = new Shape().moveTo( 0, -BULB_NECK_WIDTH / 2 ).cubicCurveTo( -BULB_BODY_HEIGHT * 0.33, -CONTROL_POINT_Y_VALUE, -BULB_BODY_HEIGHT * 0.95, -CONTROL_POINT_Y_VALUE, -BULB_BODY_HEIGHT, 0 ).cubicCurveTo( -BULB_BODY_HEIGHT * 0.95, CONTROL_POINT_Y_VALUE, -BULB_BODY_HEIGHT * 0.33, CONTROL_POINT_Y_VALUE, 0, BULB_NECK_WIDTH / 2 );
+    var bulbShape = new Shape().moveTo( 0, -BULB_NECK_WIDTH / 2 )
+      .cubicCurveTo( -BULB_BODY_HEIGHT * 0.33, -CONTROL_POINT_Y_VALUE, -BULB_BODY_HEIGHT * 0.95, -CONTROL_POINT_Y_VALUE, -BULB_BODY_HEIGHT, 0 )
+      .cubicCurveTo( -BULB_BODY_HEIGHT * 0.95, CONTROL_POINT_Y_VALUE, -BULB_BODY_HEIGHT * 0.33, CONTROL_POINT_Y_VALUE, 0, BULB_NECK_WIDTH / 2 );
     var bulbBodyOutline = new Path( bulbShape, {
       stroke: 'black',
       lineCap: 'round'

js/faradays-law/view/CoilsWiresNode.js

@@ -35,7 +35,7 @@ define( function( require ) {
     Node.call( this );
 
     // bottom coil, left bottom wire
-    var arcPoint = new Vector2( LEFT_WIRE_BULB_START.x, view.bottomCoilEndPositions.bottomEnd.y ); // bottom coil, left bottom wire, corner point;
+    var arcPoint = new Vector2( LEFT_WIRE_BULB_START.x, view.bottomCoilEndPositions.bottomEnd.y );
     this.addChild( new Path( new Shape()
       .moveToPoint( LEFT_WIRE_BULB_START )
       .lineTo( arcPoint.x, arcPoint.y - ARC_RADIUS )

js/faradays-law/view/FlipMagnetButton.js

@@ -69,12 +69,14 @@ define( function( require ) {
       .moveTo( (radius + lineWidth / 2) * Math.cos( arcStartAngle ), (radius + lineWidth / 2) * Math.sin( arcStartAngle ) ) // Inner edge of end.
       .arc( 0, 0, radius, arcStartAngle, arcEndAngle, false ); // Outer curve.
 
+    var matrix = Matrix3.translation( radius * Math.cos( arcEndAngle ), radius * Math.sin( arcEndAngle ) )
+      .timesMatrix( Matrix3.rotation2( arcEndAngle ) );
     var arrowHeadShape = new Shape()
       .moveTo( 0, 8 )
       .lineTo( 4, 0 )
       .lineTo( -4, 0 )
       .close()
-      .transformed( Matrix3.translation( radius * Math.cos( arcEndAngle ), radius * Math.sin( arcEndAngle ) ).timesMatrix( Matrix3.rotation2( arcEndAngle ) ) );
+      .transformed( matrix );
     return new Node( {
       children: [ new Path( arcShape, {
         stroke: '#000',

js/faradays-law/view/MagnetNodeWithField.js

@@ -124,7 +124,10 @@ define( function( require ) {
         magnetOffset.y = self.globalToParentPoint( event.pointer.point ).y - self.centerY;
 
         // if the user starts the drag on the magnet itself (not on the arrows), we make the arrows invisible
-        if ( event.target !== magnetTopArrowNode && event.target !== magnetBottomArrowNode && event.target !== magnetRightArrowNode && event.target !== magnetLeftArrowNode ) {
+        if ( event.target !== magnetTopArrowNode &&
+             event.target !== magnetBottomArrowNode &&
+             event.target !== magnetRightArrowNode &&
+             event.target !== magnetLeftArrowNode ) {
           model.showMagnetArrowsProperty.set( false );
         }
       },

js/faradays-law/view/VoltmeterNode.js

@@ -80,7 +80,7 @@ define( function( require ) {
 
     // position and add the label
     label.centerX = 0;
-    label.centerY = (readoutBackground.bottom + background.bottom) * 0.48; // position a little above exactly between edges
+    label.centerY = (readoutBackground.bottom + background.bottom) * 0.48;
 
     // When the text changes (via PhET-iO), re-center it
     label.on( 'text', function() {