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Between two stations a train accelerates uniformly at first, then moves with constant velocity and finally retards uniformly. If the ratio of the time taken for these is 1:8:1 and the maximum speed attained be 60 km h- then what is the average speed over the whole journey ? |
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Answer» 48 `Kmh^(-1)` `S_1=((60+0)/(2))t,S_2=60xx8t=480t` and `S_3=((60+0)/(2))t=30t` Then `v_("average")=(S_1+S_2+S_3)/(t+8t+t)` `=(30t+480t+30t)/(10t)` `=(540t)/(10t)`=54km/hour. |
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