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3 years ago

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A train 4.00 3 102 m long is moving on a straight track with a speed of 82.4 km/h. The engineer applies the brakes at a crossing

, and later the last car passes the crossing with a speed of 16.4 km/h. Assuming constant acceleration, determine how long the train blocked the crossing. Disregard the width of the crossing.

1 answer:

zysi [14]3 years ago

7 0

Answer:

The value is $t =29.2 \ s$

Explanation:

From the question we are told that

Generally the average velocity of the train is mathematically represented as

$v = \frac{u + v}{2}$

substituting 82.4 km/h for u and 16.4 km/h. for v

$v = \frac{82.4 + 16.4}{2}$

$v = 49.4 \ km/h$

Generally the time taken is mathematically represented as

$t = \frac{ L}{v}$

substituting 49.4 \ km/h for v and $4.00 * 10^2 \ m = 0.400 \ km$

$t = \frac{ 0.400}{49.4}$

$t = 0.00809 \ h$

converting to seconds

$t = 0.00809 * 3600$

$t =29.2 \ s$

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