ДАНО
T1=10 C
T2=100 C
m1=1.2 кг
m2=0.03m1 (3%)
L=2.3*10^6 Дж/кг
C=4200 Дж/кг*С
P=800 Вт -мощность плитки
КПД=65%(0.65)
t -?
РЕШЕНИЕ
полезная мощность
Pn=Q/t
время нагревания
t=Q/Pn (1)
количество тепла на нагревание
Q1=Cm1(T2-T1)
количество тепла на испарение
Q2=Lm2=L*0.03m1
общее количество
Q=Q1+Q2= Cm1(T2-T1)+L*0.03m1=m1(C(T2-T1)+L*0.03) (2)
полезная мощность
Pn=P*КПД (3)
подставим (2) и (3) в (1)
t=Q/Pn =m1(C(T2-T1)+L*0.03) /( P*КПД) <подставим данные их условия
t=1.2(4200(100-10)+2.3*10^6*0.03) /( 800*0.65)=1031.5c =17.2 мин = 0.26 ч
ОТВЕТ 1031.5c =17.2 мин = 0.26 ч
** на выбор
аквпикнр5е6пкраеркврин526462еач5кигач5а. 256н6е6а5крнпмннмн7м6пм6пм6пир7ир6мр6м6емнпмнпмнпву4а6ем4аеRead the text again and write next to the sentences True/False according to the text.
1. She looks after the big animals.
2. Her favorite animals are the tigers.
3. There are four elephants at the zoo.
4. Molly gets up at 6 o'clock.,
5. The lions eat salad.
6. The animals drink water.Read the text again and write next to the sentences True/False according to the text.
1. She looks after the big animals.
2. Her favorite animals are the tigers.
3. There are four elephants at the zoo.
4. Molly gets up at 6 o'clock.,
5. The lions eat salad.
6. The animals drink water.Read the text again and write next to the sentences True/False according to the text.
1. She looks after the big animals.
2. Her favorite animals are the tigers.
3. There are four elephants at the zoo.
4. Molly gets up at 6 o'clock.,
5. The lions eat salad.
6. The animals drink water.Read the text again and write next to the sentences True/False according to the text.
1. She looks after the big animals.
2. Her favorite animals are the tigers.
3. There are four elephants at the zoo.
4. Molly gets up at 6 o'clock.,
5. The lions eat salad.
6. The animals drink water.Read the text again and write next to the sentences True/False according to the text.
1. She looks after the big animals.
2. Her favorite animals are the tigers.
3. There are four elephants at the zoo.
4. Molly gets up at 6 o'clock.,
5. The lions eat salad.
6. The animals drink water.
Объяснение:
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