Natural Science Puzzler

Accomplished ballet dancers and basketball players often appear to "hang" in the air when jumping. This is an illusion. Once in the air, they are accelerating back towards the earth at 32 ft/s every second! One of the most accomplished leapers, Darrel Griffith, had a standing vertical jump of 4 ft that lasted a total of only 1 second. (See Problem 1.10 of the homework assignment.) But there is a reason for the illusion.

Consider Darrel Griffith's 4 ft vertical leap and answer the following questions:

Does Darrel spend more time in the air while between 0 and 2 ft from the ground or while between 2 and 4 ft? Explain.
From the very beginning to the very end of his jump, does his head move through just 4 ft? What about his knees? Explain.

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