Question

50 баллов, срочно, комнату размером 5х6х3 обогревает электрический камин мощностью 2кВТ. За сколько времени температура в комнате повысится от 10 гр. до 18 гр. удельная теплоемкость воздуха 10в3 дж/кг. Его плотность 1,33 кг/ м в3, ответ в минутах

Answer 1

Дано: V=5*6*3=80 м3;Р=2000 Вт,t1=10C,t2=18C,c=1000 Дж/кгС, р=1,33кг/м3 Найти t.Решение: Количество тепла необходимое для нагрева комнаты Q1=cm(t2-t1) = cpv(t2-t1) ; Количество тепла отданное камином Q2=А=Pt, так как потерь тепла нет,то по закону сохранения энергии Q1=Q2; cpv(t2-t1) =Pt, t=cpv(t2-t1) /P= 1,33*1000*80(18-10)/2000=425,6 c=7 мин 5,6 с

Answer 2

Calculating Time to Increase Room Temperature

To calculate the time it takes for the room temperature to increase from 10°C to 18°C when heated by a 2kW electric fireplace, we can use the formula:

Q = mcΔT

Where: - Q = heat energy required (in joules) - m = mass of air (in kg) - c = specific heat capacity of air (in J/kg°C) - ΔT = change in temperature (in °C)

First, we need to calculate the heat energy required to increase the temperature of the air in the room.

The mass of the air can be calculated using the room's volume and air density:

Volume of the room (V) = 5m x 6m x 3m = 90m³

Mass (m) = Volume x Density = 90m³ x 1.33kg/m³ = 119.7kg

The heat energy required can be calculated using the specific heat capacity of air:

Specific heat capacity of air (c) = 1.03 x 10^3 J/kg°C

Change in temperature (ΔT) = 18°C - 10°C = 8°C

Heat energy (Q) = 119.7kg x (1.03 x 10^3 J/kg°C) x 8°C = 982,524J

Now, we can calculate the time it takes for the 2kW electric fireplace to supply this amount of heat energy.

Calculating Time with Power and Energy

The power (P) supplied by the electric fireplace is 2kW, which is equivalent to 2000W.

The time (t) required to supply the heat energy can be calculated using the formula:

t = Q / P

Where: - t = time (in seconds) - Q = heat energy required (in joules) - P = power (in watts)

Converting 2kW to watts: 2kW = 2000W

Substituting the values: t = 982,524J / 2000W = 491.262 seconds

Converting seconds to minutes: 491.262 seconds ≈ 8.1887 minutes

Therefore, it will take approximately 8.2 minutes for the temperature in the room to increase from 10°C to 18°C when heated by the 2kW electric fireplace.