Problem 7.46: Riding a Loop-the-loop

annabelx4

1. The problem statement, all variables and given/known data

A car in an amusement park ride rolls without friction around the track shown in the figure . It starts from rest at point at a height above the bottom of the loop. Treat the car as a particle.

What is the minimum value of (in terms of ) such that the car moves around the loop without falling off at the top (point )?

If the car starts at height 4.00 and the radius is = 25.0 , compute the speed of the passengers when the car is at point , which is at the end of a horizontal diameter.

2. Relevant equations

mgh = 1/2 mv^2

3. The attempt at a solution

we know that h = 2 R because it's the diameter but other than that i am lost