Hai vật chuyển động với vận tốc là v1=5m/s, v2=2m/s trên một đường thẳng cùng chiều nhau. Bỏ qua ma sát giữa vật và mặt phẳng. Khối lượng hai vật là m1=200g, m2=300g a Tính động lượng của hệ hai vật b, Hai vật chuyển động đến va chạm mềm với nhau hãy tính vận tốc của hai vật sau va chạm.

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