which research method would be used in determining whether caffine suppliments improved brain performance?

The forces of push and pull

Explanation:

In the egg drop experiment, the egg is balanced on top of a toilet paper tube and balanced on a pan. The pan itself is placed on top of a glass of water. When the experimenter uses his hands to push the pan, the force of gravity pulls the egg downwards making it move down, right into the glass of water.

So the two forces which are applied in opposite directions are;

1. The force of push applied horizontally by the hand when it pushes the pan away, and

2. The force of pull caused by gravity which makes the egg move vertically downwards.