Thermal Physics: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Thermal Physics. Understanding the underlying formula is key to arriving at the correct answer below:

Using Newton's law of cooling: $\frac{70-60}{5} = K(65-T_s) \Rightarrow 2 = K(65-T_s)$ and $\frac{60-54}{5} = K(57-T_s) \Rightarrow 1.2 = K(57-T_s)$. Dividing gives $\frac{2}{1.2} = \frac{65-T_s}{57-T_s} \Rightarrow 5(57-T_s) = 3(65-T_s)$. Solving for $T_s$, we get $T_s = 45^\circ\text{C}$.