treo 1 vật vào 1 lực kế trong không khí thì lực kế chỉ 14,6N . Vẫn treo vật bằng lực kế nhưng nhúng vật chìm hoàn toàn trong nước thì lực kế chỉ 9,6N . Trọng lượng riêng của nước là 10000N/m^3 a)tính lực đẩy Ác-si-mét tác dụng lên vật. b)tính khối lượng riêng của chất làm nên vật.

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