No net energy transfer in uniform circular motion

Steps:

• Identify energy transfer as work done (force times displacement) or heat exchange.
• Evaluate each option for changes in kinetic, potential, or thermal energy.
• Check for dissipative forces like friction or explicit conversions.
• Confirm no net transfer where forces are perpendicular to motion and speeds/heights are constant.

Why D is correct:

• In circular orbit at constant height, gravity provides centripetal force perpendicular to velocity, doing no work (W = F·d cosθ = 0 when θ=90°), so mechanical energy is conserved with no transfer.

Why the others are wrong:

• A: Chemical energy in battery transfers to electrical then mechanical energy in motor.
• B: Friction on road dissipates kinetic energy as heat, transferring it to surroundings.
• C: Solar radiation transfers radiant energy to thermal energy in water.

Final answer: D