The current shape of the North American continent (the present-day territory of the United States of America and Canada) was formed 25,000 years ago. At that time the great northern icecap flowed over the North American continent. This ice flow determined the size and drainage of the Great Lakes. They changed the direction of the Missouri River and carved the channel of the Hudson River. They created the northern part of the Central Agricultural Basin, which is one of the richest farming areas in the world.
On the Atlantic shore of the United States, much of the northern coast is rocky. But the middle and southern Atlantic coasts rise gently from the sea. The Appalachians, which run almost parallel to the east coast, are old mountains with many coal rich valleys between them To the west of the Appalachians, lie plateaus built up over the centuries from bits of stone that were washed down from the mountains and then cut into small hills by streams. Beyond is the great Central Lowland which resembles the plains of Eastern Europe.
Объяснение:
Дано:
m= 2кг
t₁= 10°С
t₂=100°С
Q-?
Кількість теплоти, необхідне для нагрівання знаходимо за формулою: питому теплоємність множимо на масу і на різницю між кінцевою і початковою температурою.
Q₁ = c*m*(t₂-t₁) , де Cв=4200 Дж/кг*°С -питома теплоємність води
Q₁ = 4200*2(100-10) = 756 000 Дж = 0,756 МДж
Кількість теплоти необхідне для пароутворення:
Q₂ = m*λ , де λ = 22,6*10⁵ Дж/кг - питома теплота пароутворення
Q₂ = 2*22,6*10⁵= 4 520 000 Дж = 4,52 МДж
Кількість теплоти яку потрібно витратити :
Q = Q₁+Q₂= 756000+ 4520000 =5276000 Дж ≈ 5,3 МДж
F=60-40=20Н
po*g*V=20Н
V=20/800*10=0,0025
Fвыталкиваниявводе=po*g*V=1000*10*0,0025=25
Fпогружение=Fввоздухе-Fвыталкивания
F=60-25=35Н
ОТВЕТ:35Н. Остальные решать времени нет