A=IUt отсюда t=A/IU
t=693000Дж/220В*3,5А=900с=15мин
P = F/S , F = mg , F = 40 кг * 10 Н/кг = 400 Н , S = 0.02 м2 , P = 20000 Па
Дано:
m=3кг
t1=0°C
t2=50°C
γ=![3,4*10^{5} =340.000\frac{Dg}{kg}](https://tex.z-dn.net/?f=3%2C4%2A10%5E%7B5%7D%20%3D340.000%5Cfrac%7BDg%7D%7Bkg%7D)
с=![4200\frac{Dg}{kg*C}](https://tex.z-dn.net/?f=4200%5Cfrac%7BDg%7D%7Bkg%2AC%7D)
Найти:
Q-?
Решение:
Q=γm
Q=![340.000\frac{Dg}{kg} * 3kg = 1.020.000Dg](https://tex.z-dn.net/?f=340.000%5Cfrac%7BDg%7D%7Bkg%7D%20%2A%203kg%20%3D%201.020.000Dg)
Q=c*m*(t2-t1)
Q=![4200\frac{Dg}{kg*C} *3kg*(50-0)=630.000Dg](https://tex.z-dn.net/?f=4200%5Cfrac%7BDg%7D%7Bkg%2AC%7D%20%2A3kg%2A%2850-0%29%3D630.000Dg)
Q=Q1+Q2=1.020.000Дж+630.000Дж=1.650.000Дж=1,65мДж
Ответ: 1,65мДж