Two trains go towards each other v1 = 20 m / s v2 = 30 m / s. What is the length of the train if it rushed in 12 seconds?
| August 17, 2021 | education
V1 = 20 m / s.
V2 = 30 m / s.
t = 12 s.
L -?
The train meeting time t begins when the first car of one train meets the first car of the second train. It ends when the last car of one train is on the same level with the last car of another train. The train in time t travels the path S equal to double its length L: S = 2 * L.
The speed of one train V relative to the other will be the sum: V = V1 + V2.
The meeting time of trains t is expressed by the formula: t = 2 * L / (V1 + V2).
L = t * (V1 + V2) / 2.
L = 12 s * (20 m / s + 30 m / s) / 2 = 300 m.
Answer: the length of the train is L = 300 m.
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