To determine the force that the volleyball exerts on Ana, we can use Newton's third law of motion. Newton's third law states that for every action, there is an equal and opposite reaction. This means that any force exerted on one object will result in a force of equal magnitude but in the opposite direction being exerted on the object that applied the initial force.
Given:
- Ana exerts a force of [tex]\( 20 \, \text{N} \)[/tex] on the volleyball.
According to Newton's third law:
- The volleyball will exert a force of equal magnitude, [tex]\( 20 \, \text{N} \)[/tex], but in the opposite direction on Ana.
We can now conclude that the force the volleyball exerts on Ana is indeed:
[tex]\[ \mathbf{20 \, \text{N}} \][/tex]
Therefore, the correct answer is:
[tex]\[ \boxed{20 \, \text{N}} \][/tex]
