Answer:
gravitational potential energy
Step-by-step explanation:
Gravitational potential energy is that energy that an object possesses due to its height or vertical position. The vertical position of the object causes it to be attracted to the Earth's gravitational field, which is the basis in the name. In this case, a ball is said to roll down a ramp, which is an inclined surface.
Johanna can be said to be studying the GRAVITATIONAL POTENTIAL ENERGY because of the falling or vertical position of the ball from the ramp in response to the Earth's gravity.