## Statement

difficulty Can you say what does a ball on a table interact with and where the forces are exerted at each interaction?

## Solution

On one hand, the ball interacts by contact with the table, but it does also at distance with the ball, due to gravity. In particular the forces we can identify are the following:

• Action force exerted by the ball on the table when resting on it. It is applied on the table.
• Reaction force exerted by the table over the ball. It is applied on the table.
• Force exerted by the Earth over the ball. It is applied over the ball.
• Force exerted by the ball over the Earth. It is applied over the Earth.

## Formulas worksheet

These are the main formulas that you must know to solve this exercise. If you are not clear about their meaning, we recommend you to check the theory in the corresponding sections. Furthermore, you will find in them, under the Formulas tab, the codes that will allow you to integrate these equations in external programs like Word or Mathematica.

Formulas
Related sections
$\stackrel{\to }{{F}_{AB}}=-\stackrel{\to }{{F}_{BA}}\phantom{\rule{0ex}{0ex}}{F}_{AB}={F}_{BA}$