The gravitational potential energy of an object depends on the strength of gravity, the mass of the object, and how far it can fall. The thermal energy change of an object depends on its mass, its composition, and the temperature change it experiences. So . . . as a roller coaster starts from the top of a hill, it has ZERO kinetic energy, some potential energy, and ZERO thermal energy change. As it goes down the hill, it goes faster, decreases in elevation, and the wheels heat up from friction. Therefore, it gains KE, loses PE, and gains thermal energy.
Stability Related to forces and energy is the concept of stability.
Stability refers to an object's ability to stay in place despite small disturbances. Objects are considered stable if their center of mass remains below the support point. An example of this is in the way you stand up in a chair. Typically, you move your feet under the chair and then lean forward. This process shifts your center of mass out over your feet and you tip out of your chair.