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nguyenductuan
2 năm trước
Một đoàn tàu gồm 12 toa, mỗi toa dài 15 (m) chuyển động thẳng chậm dần đều vào ga. Một người quan sát đứng bên đường ray thấy toa thứ nhất đi qua mình trong thời gian 1,6(s), toa thứ hai đi qua mình trong thời gian 1,72(s). Chọn gốc tính thời gian là lúc đầu toa thứ nhất đi qua người quan sát. a. Tính gia tốc của đoàn tàu và tốc độ của đoàn tàu lúc toa thứ nhất bắt đầu đi ngang qua người quan sát ? b. Tính thời gian và quãng đường đoàn tàu đi được đến khi dừng hẳn ? c. Tính thời gian toa thứ sáu đi ngang qua người quan sát ? d. Sau một thời gian dừng lại ga, tàu rời ga chuyển động nhanh dần đều. Xét trên 100 thanh ray đầu, ở thanh ray thứ 10 tàu đi mất thời gian 1,2 giây. Hãy tính thời gian tàu đi qua thanh ray thứ 100 và cả 100 thanh ray này. Cho rằng các thanh ray có chiều dài bằng nhau và đặt sát nhau
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