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hungalan66
2 năm trước
một ô tô có khối lượng m=7 tấn bắt đầu chuyển động trên đường thẳng nằm ngang, vận tốc tăng từ 0 đến 60 km trong thời gian 4p và giữ nguyên vận tốc đó, lực ma sát có độ lớn Fms =500 N tác dụng vào ô tô không đổi trong suốt quá trình chuyển động. a. tính lực kéo của động cơ để xe chuyển động đều b.tính lực kéo của động cơ trong 4p trên ? c.muốn xe dừng lại, tài xế tắt máy và hãm phanh sau khi đi được 200m thì dừng hẳn. tính lực hãm phanh và thời gian hãm phanh?
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