4. A 200m long train runs at the speed of 36km / h. It takes 100s to pass through a cave. How many meters is the length of the cave

Suppose the train passes through the cave at a constant speed, and the time starts when the train head enters the cave
Then put in the formula s = t * V (s: cave length, t: time through cave, V: train speed)
Train speed: 36km / h = 36km = 36 * 1000m = 36000m
1h=3600s
So 36km / h = 36000m / 3600s = 10m / S
Suppose the length of the cave is x + 200 = 100 * 10
X=800(m)

A 100 meter long train passes through a 500 meter long cave at a constant speed. It takes 8 seconds for the train to enter the cave and ask the speed of the train in the cave
Question 2: how long does it take for the train to enter and leave the cave

100/8=12.5m/s
(100+500+100)/12.5=56s
This is the problem of junior high school

A train passes through a cave at the speed of 36km / h, the length of the cave is 920m, and the train passes through the cave for 100s. What is the length of the train, M?

Let the length of the train be X. let's see the problem clearly. The problem says that the train passes through the cave. That is to say, the tail of the train just passes through the cave. If the train is regarded as a particle, then its total moving distance is x + 920. Given the moving time and speed (the speed should be converted into meters per second, i.e. M / s), the equation x + 920 = 10m / s * 10s is established, and the solution is x = 80m

A bridge is 1.6km long. A 200m long train passes through the bridge at the speed of 15mgs. How long does it take for the train to completely pass through the bridge?

The distance of the train crossing the bridge: S = 1600m + 200m = 1800m, according to the speed formula: v = st, the time of the train crossing the bridge: T = SV = 1800m15m / S = 120s; a: the time of the train completely passing the bridge is 120s

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, let the speed of the train be v m / s, the length of the train be l m, then 60s × v = 1000m + l40s × v = 1000m − L, the solution is: v = 20m / s, l = 20m. That is, the length of the train is 200m, and the speed is 20m / s. answer: the speed of the train is 20m / S; the length is 200m

The seventh grade uses a train to cross a 1000 meter long bridge. It takes one minute to leave the bridge from the one on the bridge. The whole train is on the bridge for 40 seconds to find the train speed

If the car length is x, then
(1000 + x) / 60 = (1000-x) / 40 x = 200m
（1000+200）/60=20
The speed of the train is 20 m / s and the length is 200 m

A bridge is 1000 meters long. It takes one minute for a train to pass completely, and 40 seconds for the whole train to pass completely on the bridge?

1000+X=60V 1000-X=40V X= 200 V=20

A railway bridge is 1000 meters long. A train passes through the bridge. It takes one minute to leave the bridge. The time of the whole train on the bridge is 40 seconds. The length and speed of the train can be calculated

Let the length of the train be l m and the speed be v m / s
1000+2L=60V
1000-2L=40V
The solution of the equation is: v = 20 m / s, l = 100 m
Note: the first condition is that the locomotive is at the end of the bridge and all trains are outside the bridge, which means that the train starts to get on the bridge;
Train tail off the bridge, and all trains outside the bridge is completely off the bridge
On the bridge, the end of the train is at the end of the bridge. The whole train is on the bridge. The time from the end of the bridge to the end of the train is on the bridge

It took 22 seconds for the train to pass the 82 meter long railway bridge. If the speed of the train doubled, it took 16 seconds for the train to pass the 162 meter long railway bridge to calculate the speed and length

Let the length of the car be X
2X（x+82）/22=（162+x）/16
11（162+x）=16（x+82）
16x-11x=11*162-16*82
x=470/5
X = 94m
The original speed was (94 + 82) / 22 = 8 m / s
Later, the speed was 8 * 2 = 16 m / s

If the train passes through the bridge in 706 seconds, it will take 706 meters
A. 91B. 92C. 93D. 94

Let the length of the train body be x meters. According to the meaning of the question, we can get the equation: (82 + x) △ 22 = (706 + x) △ 100 & nbsp; & nbsp; 8200 + 100x = 15532 + 22x & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 78x = 7332 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

4. A 200m long train runs at the speed of 36km / h. It takes 100s to pass through a cave. How many meters is the length of the cave