Question 47

Kinetic Energy Increases and Potential Energy Decreases

As a roller coaster car descends a hill, its kinetic energy increases while its gravitational potential energy decreases. This is due to the conversion of potential energy into kinetic energy as the car moves downward.

A) Kinetic Energy: Increases | Potential Energy: Decreases

This option accurately describes the relationship between kinetic and gravitational potential energies during the descent of the roller coaster. As the car moves down the hill, it loses height, which reduces its gravitational potential energy, while simultaneously its speed increases, resulting in higher kinetic energy.

B) Kinetic Energy: Decreases | Potential Energy: Increases

This option is incorrect because it suggests that as the roller coaster descends, its kinetic energy decreases and potential energy increases. However, during a descent, the opposite occurs: the car speeds up, leading to an increase in kinetic energy and a decrease in potential energy.

C) Kinetic Energy: Remains constant | Potential Energy: Decreases

This option is also incorrect. While it correctly states that potential energy decreases as the car descends, it inaccurately claims that kinetic energy remains constant. In reality, kinetic energy increases as the roller coaster accelerates downhill.

D) Kinetic Energy: Remains constant | Potential Energy: Remains constant

This option is incorrect as well. It suggests that both kinetic and potential energies do not change as the roller coaster descends, which contradicts the principles of energy conversion in a gravitational field.

Conclusion

Option A is definitively correct because it accurately reflects the physical principles of energy conversion during the descent of a roller coaster car. As the car drops in height, gravitational potential energy is converted into kinetic energy, resulting in increased speed. All other options fail to represent this fundamental concept, making A the only valid choice.