Which of the following scenarios best illustrates $\mathrm{kinetic} \mathrm{energy}$ being converted into $\mathrm{potential} \mathrm{energy}$?

• A. A ball thrown upward slows down as it rises, storing $\mathrm{energy}$ due to its $\mathrm{height}$ above the ground.
• B. A compressed spring is released and launches a block across a table.
• C. A ball rolling down a hill speeds up as it descends.
• D. A car engine burns fuel to move the car forward.

Answer: (A)

Verified step by step guidance

1. Understand the definitions: Kinetic energy is the energy an object has due to its motion, given by the formula \(E_k = \frac{1}{2} m v^2\), where \(m\) is mass and \(v\) is velocity. Potential energy is the energy stored due to an object's position or configuration, often gravitational potential energy given by \(E_p = m g h\), where \(g\) is acceleration due to gravity and \(h\) is height.
2. Identify the process of energy conversion: When kinetic energy decreases and potential energy increases, it means the object is slowing down while gaining height or storing energy in some form of position or configuration.
3. Analyze the first scenario: A ball thrown upward slows down as it rises. Its velocity decreases, so kinetic energy decreases, while its height increases, so gravitational potential energy increases. This is a direct conversion of kinetic energy into potential energy.
4. Check the other scenarios: A compressed spring launching a block converts potential energy (stored in the spring) into kinetic energy, not the other way around. A ball rolling down a hill converts potential energy into kinetic energy as it speeds up. A car engine burning fuel converts chemical energy into kinetic energy and other forms, not specifically kinetic to potential energy.
5. Conclude that the scenario where a ball thrown upward slows down as it rises best illustrates kinetic energy being converted into potential energy.