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vanthien
2 năm trước
khối sắt nặng 15kg có nhiệt độ 20 độ C , cho khối sắt vào lò than nung lên trong 15 phút rồi lấy ra nhiệt độ khối sắt sau khi lấy ra là 820 độ C. Tính lượng than cần dùng để nung khối sắt trong 1 giờ khi 10% nhiệt từ lò than truyền sang khối sắt biết nhiệt dung riêng của sắt là 460J/(Kg.K)và năng suất tỏa nhiệt của than là 3,6.10^6 KJ/kg.
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