Emergency. The length of the train is 200m, the length of the bridge is 1000m, and the train passes through the bridge at a constant speed Emergency. The length of the train is 200m, the length of the bridge is 1000m, and the train passes through the bridge at a constant speed. (1) the time for the train to pass through the bridge? (2) what is the time for the train to finish at the bridge? (3) the time for the train driver to pass through the bridge? Note: This is a physics problem

Emergency. The length of the train is 200m, the length of the bridge is 1000m, and the train passes through the bridge at a constant speed Emergency. The length of the train is 200m, the length of the bridge is 1000m, and the train passes through the bridge at a constant speed. (1) the time for the train to pass through the bridge? (2) what is the time for the train to finish at the bridge? (3) the time for the train driver to pass through the bridge? Note: This is a physics problem

To give the speed of the train, 1. The time for the train to pass the bridge is calculated from the time when the locomotive gets on the bridge and the end when the train leaves the bridge. The total distance is (1000 + 200) M. divide the distance by the speed of the train. 2. Divide the distance by (1000-200) M. divide the speed by the time. 3. 1000 m divided by the speed,

An iron bridge is 1000 meters long. A train passes through the bridge. It takes one minute for the train to get on the bridge and then completely cross the bridge. The time for the whole train to be completely on the bridge is 40 seconds (from the rear of the train to the front of the train about to get off the bridge). How about the speed and length of the train?

1 minute = 60 seconds, all pass: S1 = l bridge + L, T1 = 60s, all on the bridge: S2 = l bridge - L, T2 = 40s, suppose the speed of the train is v m / s, the length of the train is l m, then 60s × v = 1000m + l40s × v = 1000m − L, the solution is: v = 20m / s, l = 20m

It is known that the length of a railway bridge is 1000m. A train passes through the bridge. It is measured that it takes 50s for the train to cross the bridge completely. The time of the whole train on the bridge is 20s. The speed and length of the train on the bridge are calculated
emergency

If the length of the train is x, then the distance of the train from the beginning of the bridge to the complete bridge is (1000 + x), and the length of the whole train on the bridge is (1000-x)
So (1000 + x) / 50 = (1000-x) / 20
2000+2x=5000-5x
7x=3000
The length of the train is: x = 428.57m
The train speed is: (1000 + 428.57) / 50 = 28.57 M / s

An iron bridge is 1000 meters long. A train passes through the bridge. It takes one minute for the train to get on the bridge and then completely cross the bridge. The time for the whole train to be completely on the bridge is 40 seconds (from the rear of the train to the front of the train about to get off the bridge). How about the speed and length of the train?

1 minute = 60 seconds, all pass: S1 = l bridge + L, T1 = 60s, all on the bridge: S2 = l bridge - L, T2 = 40s, suppose the speed of the train is v m / s, the length of the train is l m, then 60s × v = 1000m + l40s × v = 1000m − L, the solution is: v = 20m / s, l = 20m

A 100m long train passes through a 500m long cave at a speed of 43.2km/h,
How many seconds does it take for a 100 m long train to cross a 500 m long cave at a speed of 43.2 km / h? How long does it take for the train to run completely in the cave?
Online. Come on

43.2*1000/3600=12m/s
t1=（100+500）/12=50s
t2=(500-100）/12=33.33s

It takes 50 seconds for a train to cross a 900 meter long cave and 20 seconds to cross a 300 meter long bridge at the same speed

Vehicle speed = (900-300) / (50-20) = 20 m / S
Vehicle length = 20 * 50-900 = 100m

It took one-third of a minute for a train to travel at a constant speed from the 300m bridge to the full bridge

Your question hasn't been sent out completely. It is estimated that it is similar to the following question. Sending the following for reference may solve your original problem
It takes 20 seconds for a train to run at a constant speed through a 300 m long tunnel. There is a light on the top of the tunnel, which shines vertically downward. The time for the light to shine on the car is 10 seconds. Find the length of the car
Suppose the length of the train is x meters
Because the time of the train passing through the tunnel is calculated from the beginning when the front of the train enters the tunnel and the end when the rear of the train leaves the tunnel. In this period of time, the train has traveled x + 300 meters, so according to the meaning of the title: the train has moved x + 300 meters in 20 seconds, and the speed of the train is equal to (x + 300) / 20 meters / second
From another point of view: because the light on the top of the tunnel does not move, the time that the light shines on the car is from the light bulb to the front of the car, until the light bulb to the rear of the car. In this period of time, the train travels x meters, so according to the meaning of the title: the train moves x meters in 10 seconds, so the speed of the train is equal to X / 10 meters / second
Because the speed of the train is the same quantity in this problem
So we get the equation: (x + 300) / 20 = x / 10
The solution is x = 300
A: the length of the train is 300 meters

It takes one minute for a 100 meter long train to pass through a 500 meter long cave. Find out the speed of the train passing through the cave

If the train is 100 meters long and the cave is 500 meters long, it should be calculated from the front of the train to the cave. If the tail of the train goes out of the cave, it is 500 meters long + the length of the train is 100 meters, 1min = 60s
（100+500）/60s=10m/s=36km/h

If it takes one minute for a 100 m long train to cross a 620 m cave, what is the average speed of the train? How long does it take to drive 21.6km at this speed?

(1) The distance of the train through the cave is s = l Car + L cave = 100m + 620m = 720m, the speed of the train: v = st = 720m, 60s = 12m / S. (2) the time required to travel 21.6km at this speed: t '= s' = 21600m12 M / S = 1800s = 0.5h

When a train passes a 1300m bridge at a speed of 90km / h, it takes just 1min for the train to pass through the bridge. If the train passes at the same speed, it will take only 1min
The time of the whole train completely in the tunnel is 40 s
What's the length of the tunnel? I figured it out to be 1200m,

Let the length of the train be X
Speed 90km / h = 25m / S
(1300 + x) / 25 = 60, so x = 200m
The tunnel length is y
（y-200）/25=40,y=1200m
So your answer is right