Question

when will the potential energy of this roller coaster car be gone? when the car reaches the bottom of the track never

Explanation:

Potential energy is calculated using the formula \(PE = mgh\) (where \(m\) is mass, \(g\) is acceleration due to gravity, and \(h\) is height). As long as the roller - coaster car has a non - zero height (\(h>0\)) relative to a reference point (usually the ground), it will have potential energy. Even when it reaches the "bottom" of the track, it still has some height above the center of the Earth (since the Earth's radius \(R\approx6371\times10^{3}\text{ m}\) and the height \(h\) of the car above the Earth's center is \(h = R + y\), where \(y\) is its height above the ground level at the track's bottom). Since \(h\) is always greater than zero (because the car is on the surface of the Earth and not at the Earth's center), the potential energy \(PE=mgh\) will never be zero.

Answer:

never