Normal reaction at Dubbs Reservoir

 

The force that a surface exerts upwards on an object perpendicular to the surface has had a rebranding. It was the Normal reaction force. Now it is the Normal contact force. I've started referring to it as the normal reaction contact force. I've always said that "reaction" shows that it isn't there until an object is placed on the surface, but I suppose "contact" now shows that. It is an electromagnetic force because it is due to positive nuclei repelling as the push of the object on the surface tries to force the nuclei closer. Some people label the upwards arrow R as they have done here beside Dubbs Reservoir above Troutbeck. Other people label it N.