Question

. Стальной молоток был нагрет для закалки до температуры 720 °С, затем быстро охлажден до температуры 10°С. При этом он отдал окружающей среде 298,2 кДж энергии. Найти массу молотка.

Answer 1

Количество теплоты равно удельной теплоемкости умноженной на массу и разность температуры:
c = 462 Дж/кг град
Q = c*m*(t1-t2),  
отсюда: 298200 = 462*m*710
 m = 298200/462/710 = 0.9 кг
Масса молотка около 1 кг.

Answer 2

Answer in detail. A steel hammer was heated for quenching to a temperature of 720 °C, then quickly cooled to a temperature of 10 °C. In doing so, it gave off 298.2 kJ of energy to the surrounding environment. Find the mass of the hammer.

To find the mass of the hammer, we need to use the formula for the heat transfer during cooling:

$$Q = mc\Delta T$$

where $Q$ is the amount of heat transferred, $m$ is the mass of the object, $c$ is the specific heat capacity of the material, and $\Delta T$ is the change in temperature.

We know that $Q = -298.2$ kJ, since the hammer loses heat to the environment. We also know that $\Delta T = 10 - 720 = -710$ °C, since the hammer cools down from 720 °C to 10 °C. We need to find the value of $c$ for steel, which is the material of the hammer. According to one of the web search results, the specific heat capacity of steel is about $0.46$ kJ/kg°C.

Substituting these values into the formula, we get:

$$-298.2 = m \times 0.46 \times (-710)$$

Solving for $m$, we get:

$$m = \frac{-298.2}{0.46 \times (-710)}$$

$$m \approx 0.93 \text{ kg}$$

Therefore, the mass of the hammer is about 0.93 kg.