Chapter SH, Problem 8.2APP

To determine

To calculate: Mechanical energy produced by an engine when $\text{1 kg}$ of gasoline is burned.

Answer to Problem 8.2APP

Mechanical energy produced by an engine when $\text{1 kg}$ of gasoline is burned is $\underset{\_}{12000\text{ kJ}}$ .

Explanation of Solution

Given:

Efficiency = $\text{25\%}$

Energy released in burning $\text{1 kg}$ of gasoline = $\text{48000 kJ}$

Formula used:

Efficiency is given by,

  $e=\frac{W_{\text{out}}}{W_{\text{in}}}\times 100$

Where $W_{\text{out}}$ is output work and $W_{\text{in}}$ is input work.

Calculation:

Mechanical energy produced by an engine when $\text{1 kg}$ of gasoline is burnedcalculated as:

  $\begin{array}{l}e=\frac{W_{\text{out}}}{W_{\text{in}}}\times 100\\ W_{\text{out}}=\frac{e\times W_{\text{in}}}{100}\\ W_{\text{out}}=\frac{25\times 48000\text{ kJ}}{100}\\ W_{\text{out}}=12000\text{ kJ}\end{array}$

Conclusion:

Mechanical energy produced by an engine when $\text{1 kg}$ of gasoline is burned is $\underset{\_}{12000\text{ kJ}}$ .