Chapter SH, Problem 5.5APP

To determine

To calculate: Mass of the concrete statue.

Answer to Problem 5.5APP

Mass of the concrete statue is $\underset{\_}{6\text{ kg}}$ .

Explanation of Solution

Given:

Specific heat = $\text{600 J/}\left(\text{kg}\cdot °\text{C}\right)$

Initial temperature = $40°\text{C}$

Final temperature = $15°\text{}\text{C}$

Change in thermal energy = $-90000\text{ J}$

Formula used: Change in thermal energy is given by,

  $Q=m\left(T_{\text{f}}-T_{\text{i}}\right)C$

Where $m$ is mass, $T_{\text{f}}$ is final temperature, $T_{\text{i}}$ is initial temperature and C is specific heat.

Calculation:

Mass is calculated as:

  $\begin{array}{l}Q=m\left(T_{\text{f}}-T_{\text{i}}\right)C\\ m=\frac{Q}{\left(T_{\text{f}}-T_{\text{i}}\right)C}\\ m=\frac{-90000\text{ J}}{\left(15°\text{C}-40°\text{C}\right)\left(\text{600 J/}\left(\text{kg}\cdot °\text{C}\right)\right)}\\ m=\frac{-90000\text{ J}}{\left(-25°\text{C}\right)\left(\text{600 J/}\left(\text{kg}\cdot °\text{C}\right)\right)}\\ m=6\text{ kg}\end{array}$

Conclusion:

Mass of the concrete statue is $\underset{\_}{6\text{ kg}}$ .