In 1939 a man named Joe Sprinz tried to set a world record for catching a baseball dropped from the greatest height. He tried to catch a ball dropped from a blimp 800 ft above him. On his fifth try he succeeded, but the ball slammed the glove into his face, breaking his jaw in 12 places, knocking out five teeth, and knocking him unconscious. As you might have guessed, the ball was really moving when it reached him. Air slows that ball appreciably, but you can get a pretty good idea of how fast the ball was moving even if you neglect air resistance. How long would you estimate the ball took to fall 800 ft, and how fast was it going when it hit Joe. You may want to convert feet to meters.

Well, it says estimate, so let's estimate. since it's a bit less than 3 ft in a meter, 800 ft is about 30m. Now, let's say the ball was just let go instead of being flung at poor Joe, so it's initial velocity is 0. Law of motion will be [tex]30=5t^2[/tex] (where acceleration due to gravity is rounded to 10), or [tex]t=\sqrt 6 \approx 2.5s[/tex]. At this point, the ball would have reached a speed of [tex]v= 10(2.5) = 25 m/s[/tex] That's about 55 mph