diff --git a/Code/OysterPhysics3D/OysterPhysics3D.h b/Code/OysterPhysics3D/OysterPhysics3D.h
index f814ff46..c6eca8e8 100644
--- a/Code/OysterPhysics3D/OysterPhysics3D.h
+++ b/Code/OysterPhysics3D/OysterPhysics3D.h
@@ -59,11 +59,20 @@ namespace Oyster { namespace Physics3D
 
 		/******************************************************************
 		 * Returns the world tangential momentum at worldPos, of a mass in rotation.
+		 * G = ( H x r ) / ( |H| * |r|^2 ) <-> H = r x G
 		 * @todo TODO: improve doc
 		 ******************************************************************/
 		inline ::Oyster::Math::Float4 TangentialLinearMomentum( const ::Oyster::Math::Float4 &angularMomentum, const ::Oyster::Math::Float4 &worldOffset )
 		{
-			return ::Oyster::Math::Float4( angularMomentum.xyz.Cross(worldOffset.xyz), 0.0f ) /= worldOffset.Dot( worldOffset );
+			::Oyster::Math::Float magnitudeH_squared = angularMomentum.Dot( angularMomentum );
+			if( magnitudeH_squared > 0 )
+			{
+				return ::Oyster::Math::Float4( angularMomentum.xyz.Cross(worldOffset.xyz), 0.0f ) /= ( (::Oyster::Math::Float)::std::sqrt(magnitudeH_squared) * worldOffset.Dot( worldOffset ) );
+			}
+			else
+			{
+				return ::Oyster::Math::Float4::null;
+			}
 		}
 
 		/******************************************************************