Question
B3.3 Useful Energy and Efficiency pages 215-220 Useful Energy The purpose of a machine is to convert the initial energy input to the type of desired energy output. Energy input refers to the __ Useful energy output refers to the __ . All energy output that is not being used to do useful work is considered __ (e.g. energy lost due to friction). State the input energy.useful output energy, and waste energy in the following situations: 1. Light bulb 2. Truck 3. Human Body __ - Percent efficiency is calculated using the following formula:
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Kevin
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Answer
Energy input refers to the **total energy supplied to a machine**.Useful energy output refers to the **energy converted by the machine into the desired form**.All energy output that is not being used to do useful work is considered **waste energy** (e.g., energy lost due to friction).State the input energy, useful output energy, and waste energy in the following situations:1. **Light bulb:** * **Input energy:** Electrical energy * **Useful output energy:** Light energy * **Waste energy:** Heat energy2. **Truck:** * **Input energy:** Chemical energy (from fuel) * **Useful output energy:** Kinetic energy (motion) * **Waste energy:** Heat energy (from engine), Sound energy3. **Human Body:** * **Input energy:** Chemical energy (from food) * **Useful output energy:** Kinetic energy (movement), Thermal energy (body heat) * **Waste energy:** Heat energy (from metabolic processes)Percent efficiency is calculated using the following formula:**Efficiency = (Useful energy output / Total energy input) x 100%**