Question
5. A typical combustion engine is 25% efficient. Calculate the amount of thermal energy produced by a combustion engine Assume it consumes 3.5times 10^9J of chemical potential energy. (3)
Solution
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HannahMaster · Tutor for 5 years
Answer
Here's how to calculate the thermal energy produced by the combustion engine:
**1. Understand Efficiency:**
Efficiency is the ratio of useful output energy to the total input energy. In this case, the useful output is the mechanical work done by the engine, and the input is the chemical potential energy of the fuel. The remaining energy is lost as heat (thermal energy).
**2. Calculate Useful Output Energy:**
Since the engine is 25% efficient, it converts 25% of the chemical potential energy into useful mechanical work.
Useful Output Energy = Efficiency × Input Energy
Useful Output Energy = 0.25 × 3.5 × 10⁹ J
Useful Output Energy = 8.75 × 10⁸ J
**3. Calculate Thermal Energy Produced:**
The thermal energy produced is the difference between the total input energy and the useful output energy.
Thermal Energy = Input Energy - Useful Output Energy
Thermal Energy = 3.5 × 10⁹ J - 8.75 × 10⁸ J
Thermal Energy = 2.625 × 10⁹ J
**Answer:** The combustion engine produces 2.625 × 10⁹ J of thermal energy.
**1. Understand Efficiency:**
Efficiency is the ratio of useful output energy to the total input energy. In this case, the useful output is the mechanical work done by the engine, and the input is the chemical potential energy of the fuel. The remaining energy is lost as heat (thermal energy).
**2. Calculate Useful Output Energy:**
Since the engine is 25% efficient, it converts 25% of the chemical potential energy into useful mechanical work.
Useful Output Energy = Efficiency × Input Energy
Useful Output Energy = 0.25 × 3.5 × 10⁹ J
Useful Output Energy = 8.75 × 10⁸ J
**3. Calculate Thermal Energy Produced:**
The thermal energy produced is the difference between the total input energy and the useful output energy.
Thermal Energy = Input Energy - Useful Output Energy
Thermal Energy = 3.5 × 10⁹ J - 8.75 × 10⁸ J
Thermal Energy = 2.625 × 10⁹ J
**Answer:** The combustion engine produces 2.625 × 10⁹ J of thermal energy.
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