A roller coaster ride includes a circular loop with radius R = 11.6 m. What minimum speed must the car have at the top to stay in contact with the tracks?

Question

How would I go around solving this, as in what formula would I need?

Answer 1

The centripetal acceleration is given by v²/r m/s².
Acceleration due to gravity is g=9.8 m/s²

If one is to offset the other, they must be equal. at the highest point of the loop.

So set
v²/r = g
to solve for v.
Note: at this speed, the normal force on the track is zero.