If you remember, the problem statement told us that the typical adult human eye has a vertical distance from lid-to-lid of 12 millimeters, and if you look at the diagram at the left, that is the same thing as the magnitude of the displacement of the upper eyelid as it closes.
If the size of the displacement is 12 millimeters, what is the sign of the displacement of the upper eyelid as it closes? Complete the self-quiz below to find out.
What is the Sign of Displacement? Self-Quiz
Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!