Question

Стальной утюг массой 800 г нагрелся на 50С за 2 минуты. Чему равна мощность утюга, если его КПД составляет 75% Подробно с решением!!! ​

Answer 1

800 г = 0,8 кг
2 мин =120 с
480 Дж/кгС - удельная теплоемкость стали
Q=480*0,8*50=19200 Дж
P = Q / t
19200/120=160 Вт
160 - 75%
P = 160/0,75=213,(3) Вт

Answer 2

Calculation of Power

To calculate the power of the iron, we can use the formula:

Power (P) = Energy (E) / Time (t)

The energy can be calculated using the formula:

Energy (E) = Mass (m) * Specific Heat Capacity (c) * Change in Temperature (ΔT)

Given: - Mass of the iron (m) = 800 g = 0.8 kg - Change in temperature (ΔT) = 50°C - Time (t) = 2 minutes = 2 * 60 seconds = 120 seconds - Efficiency (η) = 75% = 0.75 (as a decimal)

First, let's calculate the energy using the given values:

Energy (E) = 0.8 kg * c * 50°C

The specific heat capacity (c) of iron is approximately 450 J/kg°C Substituting this value into the equation:

Energy (E) = 0.8 kg * 450 J/kg°C * 50°C

Now, let's calculate the power:

Power (P) = Energy (E) / Time (t)

Substituting the values:

Power (P) = (0.8 kg * 450 J/kg°C * 50°C) / 120 seconds

Simplifying the equation:

Power (P) = (0.8 kg * 450 J/kg°C * 50°C) / 120 seconds

Power (P) = 150 J/s

Therefore, the power of the iron is 150 watts.

Summary:

The power of the iron, given that it heated up by 50°C in 2 minutes and has an efficiency of 75%, is 150 watts.

Please note that the specific heat capacity value used for iron is an approximation and may vary slightly depending on the source.