You build a loop-the-loop in your backyard. It has a diameter of 3.10 m.
a) How fast will you have to be moving at the top of the loop to avoid falling off? The answer I got was 3.90 m/s. Is this correct?
b)If you'll be coasting from the time you get to the bottom of the loop, how fast will you have to be going at the bottom?
a) looks good
b) you know the kinetic energy at the top
... just add the gravitaional potential (mgh) across the loop to find the bottom speed