Question

how are kinetic energy and thermal energy related?
kinetic energy only exists in moving objects, while thermal energy only exists in solids.
kinetic energy and thermal energy are completely unrelated types of energy.
thermal energy is the potential energy stored in chemical bonds, not related to kinetic energy.
thermal energy is the total kinetic energy of particles in a substance.

Explanation:

1. Analyze the first option: Thermal energy exists in all states of matter (solids, liquids, gases), so the claim that thermal energy only exists in solids is wrong. Kinetic energy is for moving objects, but this option's thermal energy part is incorrect.
2. Analyze the second option: Kinetic and thermal energy are related (thermal energy involves particle kinetic energy), so they are not completely unrelated. This option is wrong.
3. Analyze the third option: Thermal energy is not potential energy in chemical bonds (that's chemical potential energy). Thermal energy is about particle motion, so this option is wrong.
4. Analyze the fourth option: Thermal energy is the total kinetic energy of the particles (atoms/molecules) in a substance. As particles move (have kinetic energy), the sum of their kinetic energies is thermal energy. This matches the relationship.

Answer:

D. Thermal energy is the total kinetic energy of particles in a substance. (Note: Assuming the options are labeled A - D in order, with the last option being D. If the original labeling was different, adjust the identifier, but the text is "Thermal energy is the total kinetic energy of particles in a substance.")