An empty jug of weight "W" rests on the table. What is the support force exerted on the jug by the table?

An empty jug of weight "W" rests on the table. What is the support force exerted on the jug by the table? What is the support force when water of weight "w" is poured into the jug?

 

Answer

It might be easier if you draw a diagram, but basically, the jug isn't going anywhere (flying off the table) so: The downward force on the jug is just it's weight (which equals its mass * g). The force exerted on the jug by the table is called the "normal force". This force is equal but opposite to the downward force. So, it is just -W. For the second part, the jug now weighs (W+w). This is the downward force. The upward force is -(W+w). This is a nice little demonstration of Newton's Laws. Source(s): http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html