Calculation: a train passes through a 1800m long tunnel at a uniform speed of 20m / s. It is measured that the time required for the train to completely pass through the tunnel is 108s. Calculate: (1) What is the length of the train? (2) How long did the train run in the tunnel?

Calculation: a train passes through a 1800m long tunnel at a uniform speed of 20m / s. It is measured that the time required for the train to completely pass through the tunnel is 108s. Calculate: (1) What is the length of the train? (2) How long did the train run in the tunnel?

(1) The distance the train travels completely through the tunnel:
Because the speed v = 20m / s, t = 108s
So s = VT = 20m / S × 108s=2160m
Tunnel s = 1800m
Therefore, s car = S-S tunnel = 2160m-1800m = 360m;
(2) The total distance of the train running in the tunnel:
S1 ＾ l tunnel - L car = 1800m-360m = 1440m,
Time T1 = S1 for all trains running in the tunnel
v=1440m
20m/s=72s．
So the answer is: (1) the length of the train is 360m;
(2) The running time of all trains in the tunnel is 72s

A 360m long train passes through a 1800m long tunnel at a constant speed. It is measured that it takes 108s for the train to pass through the tunnel completely The running speed of the train (unit: M / s), how many km / h, (1800 + 360) / 108 = 20 m / S Why count the conductor of the train?

20m/s=72Km/h
When the locomotive enters the tunnel and the tail of the train leaves, the distance from the locomotive to the tunnel exit is equal to the length of the train

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Derivation of root sign (x * (1 -- x)) = (1-2x) / (2 root signs (x (1-x))
Arcsin root x derivation / root (x * (1 -- x)) derivation = 1 / (1-2x)
When x tends to 0, it tends to 1

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This problem may be a little difficult for you
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