As is often said here and in XKCD, an orbit isn't merely high up... it's also going fast. The first two American astronauts -- Alan Shepard and Gus Grissom -- did indeed get "high up" enough to qualify as being in space (well above the Karman line). But their flights were "sub-orbital", and they fell back down before making it all the way around the Earth. Let's see if they were "going fast."
What was the maximum speed each achieved by Shepard and Grissom? (You may use whatever units are convenient.)
What speed would they have needed to acheive orbit?
In percent, how did their maximum speeds compare to orbital velocity?
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