Question

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?

Answer 1

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