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haphuongnb6
2 năm trước
.Một người công nhân nâng 10 thùng hàng mỗi thùng nặng 20 kg lên kệ cao 60 cm mất 4 min . Một công nhân khác nâng được 15 thùng hàng mỗi thùng nặng 16 kg lên kệ cao 50 cm trong 5 min . Hãy so sánh công suất của 2 người này ? ĐS : Ƥ1 = 5W > Ƥ2 = 4W
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