____________________ A clapper stays in synch with the echo of the clapping. During ten seconds of clapping there were 40 claps. The echo flight distance out to the building and back was 87 meters. Determine the speed of sound based on this data.
What is presbyopia?
What is the typical treatment for presbyopia?
On the diagram below, draw the path of a light ray from the penny to the eye.
__________________ When spear fishing in shallow water on the reef,
does the experienced spear fisher aim above or below the fish that he sees in the water?