Which of the following actions represents a conversion of chemical energy into mechanical energy?

• A. A person running after eating food
• B. A battery powering a radio
• C. Ice melting in a warm room
• D. A flashlight emitting light

Answer: (A)

Verified step by step guidance

1. Understand the types of energy involved: Chemical energy is stored in the bonds of molecules and can be released during chemical reactions. Mechanical energy is the energy associated with motion or position of an object.
2. Analyze each option to identify if chemical energy is being converted into mechanical energy:
3. 1. A person running after eating food: The food contains chemical energy stored in its molecules. The body metabolizes this food, converting chemical energy into mechanical energy to enable muscle movement.
4. 2. A battery powering a radio: The battery converts chemical energy into electrical energy, which then powers the radio. This is chemical to electrical energy conversion, not mechanical.
5. 3. Ice melting in a warm room: This is a physical change where thermal energy causes a phase change; no chemical energy is involved or converted into mechanical energy.
6. 4. A flashlight emitting light: The battery converts chemical energy into electrical energy, which is then converted into light energy, not mechanical energy.
7. Conclude that the only option where chemical energy is directly converted into mechanical energy is the person running after eating food.