At the top of the loop, two main forces are at play: gravity (
) and the normal force from the track. For the "minimum" speed (the point where the car just stays on the track), the normal force is zero. We use: ≈is approximately equal to 2. Set up the equation a-roller-coaster-has-a-vertical-loop-with-radius-of-15m
The minimum speed required for the roller coaster to stay on the track at the top of a radius loop is . At the top of the loop, two main