The physics
A body on a curve needs a pull toward the curve's centre: mv²/R.
At the top of a hump, the centre is below the car. Gravity pulls down. The road pushes up with N. So mg − N = mv²/R.
hump: N = m g − m v² / R dip: N = m g + m v² / R
Go faster, and N gets smaller. At N = 0, the wheels leave the road. That happens at v = √(gR).
A block on a smooth dome speeds up as it slides. At angle θ from the top, v² = 2gR(1 − cos θ). It leaves when the dome's push falls to zero.
m g cos θ − N = m v² / R it leaves at N = 0
Any curved path fits a circle at each point. Its radius is the radius of curvature. Only the acceleration across the path bends it.
r = v² / a⊥ top of a throw: r = (u cos θ)² / g