A copper block of mass ${3.6}\,\text{kg}$ at ${86}\,^\circ\text{C}$ is dropped into a bucket holding ${2.4}\,\text{L}$ of water at $10\,^\circ\text{C}$. The ambient temperature is $25\,^\circ\text{C}$, but you may assume that heat transfer between the copper and the water is much faster than that between either and the surroundings. What temperature is reached when the copper and water first come to equilibrium with one another? Answer: $T =$ $\,^\circ\text{C}$ (answer tolerance: $0.5\,^\circ\text{C}$)