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A train with a length of 300m crosses the bridge at a speed of 36km / h. It is known that it takes 5min for all trains to pass through the bridge, so the bridge length can be calculated rt
v=36*1000/3600=10m/s
t=60*5=300s
X=vt=10*300=3000m
Bridge length L = x-l1 = 3000-300 = 2700m
A train passes through a 500 meter long tunnel at a constant speed. If the train starts to enter the tunnel and leaves completely, it takes 30 seconds, while the whole train is completely in the tunnel for 20 seconds
Ask for the length of the train, explain the reason and describe it in proper language
Using linear equation of one variable
From the beginning of the train into the tunnel to completely out, the forward distance is: tunnel length + train length, takes 30 seconds
The length of the whole train in the tunnel is: tunnel length - train length takes 20 seconds
Let v be the train speed and l be the train leader
30V=500+L 20V=500-L
The solution is: l = 100m
The train is 100 meters long
Solution of one variable linear equation: from the beginning of the train entering the tunnel to completely leaving, the forward distance is: tunnel length + train length, which takes 30 seconds
The length of the whole train in the tunnel is: tunnel length - train length takes 20 seconds
The train is x meters long
Train speed = (500 + x) / 30 = (500-x) / 20, the solution is x = 100, so the train is 100 meters long
It takes 50s for a train to pass through a 500m long tunnel, and 35S for a train to pass through a 300m long tunnel at the same speed
RT
Equation ~ equation! And it's a linear equation of one variable!
Let the length of the train be x meters
（x+500）/50=（x+300）/35
The solution is x = 500 / 3
The length of the train is 500 / 3M, about 166.66m
It's a strange number, but it's true
When a train goes at a speed of 38m / s and whistles at a distance of 600m from a tunnel entrance, when the train driver hears the echo, how far is the locomotive from the tunnel entrance
When a train is moving at a speed of 38m / s and honks at a distance of 600m from a tunnel entrance, when the train driver hears the echo, how far is the locomotive from the tunnel entrance?
The sound speed is 340 m / s
Let's hear the echo after X
The distance the car moves is 38x
The distance of sound motion is 340x
38X+340X=2S=600*2=1200 m
X=1200/378 s
The distance of train movement is 38x = 120 M
The distance between the train and the tunnel is 600-120 = 480 M
It takes 100 seconds for a train to pass a bridge at the speed of 15 m / s
∵ v = st, v = 15m / s, ∵ s = s Bridge + s car, ∵ s Bridge = S-S car = 1500m-200m = 1300m. A: the length of the bridge is 1300m
It takes 100 seconds for a 200m train to pass a bridge at the speed of 15m / s, and the bridge length is calculated
1300 or 1700
When you look at the problem like this, you start from the end of the bridge. If you pass the bridge completely, you have to cross the bridge at the end of the car. So the car should not cross the bridge until it is 200 meters above the end of the bridge. So the key to the whole problem is from the beginning of the car to the end of the car
（x+200）/15=100
The solution is x = 1300. So the bridge is usually 1300 meters
A 200m long train passes through the bridge at the initial speed of 2m / s and leaves the bridge at the speed of 10m / s after 100s? (2) If the bridge is 400m long, what is the speed of the train passing the bridge at a constant speed in the same time?
(1) According to the speed time formula, a = V2 − v1t = 10 − 2100m / S2 = 0.08m/s2. (2) the speed of the train passing the bridge at a uniform speed v = x + LT = 400 + 200100m / S = 6m / s. answer: (1) the acceleration of the train passing the bridge is 0.08 & nbsp; m / S2. (2) the speed of the train passing the bridge at a uniform speed is 6m / s in the same time
It takes 2 minutes for a train to pass a bridge at a speed of 15 m / s with a length of 200 m. We can find out (1) the distance of the train in this period, (2) the length of the bridge and (3) the time of all trains running on the bridge
It's a process
1.s=vt=15m/sX120s=1800m
2.s=1800-200m=1600m
3t=s/t=1600m/15m/s=106.67s
It takes two minutes for a 200m long train to cross a 1000m long tunnel, and then pass the 2.4km long bridge at this speed. How long does it take to cross the bridge?
First of all, we need to understand that the so-called "passing through the tunnel" refers to the distance from the front of the train to the rear of the train, which is 200 + 1000 = 1200 meters. According to this, we can calculate the speed of the train, 2 minutes = 120 seconds (1000 + 200) / 120 = 10m / s. similarly, passing through the bridge refers to the distance from the front of the train to the rear of the train leaving the bridge, which is 2400 + 200 = 2600 meters, so the time is 2600 / 10 = 260 seconds = 4 minutes 20 seconds
A freight car is running on the straight road at the speed of V1 = 28.8km/h. Due to the wrong scheduling, a passenger car behind it is driving on the same road at the speed of V2 = 72km / h. at the distance of S0 = 600m, the driver of the passenger car immediately stops the truck. In order to avoid collision, at least how much speed should the passenger car speed up?
Taking the direction of the vehicle as the positive direction, let the acceleration of the passenger car after braking be A2. From the above non collision condition, we get that v2t − 12a2t2 ≤ v1t + S0 & nbsp; ①; v2-a2t ≤ v1. ② when the braking acceleration takes the minimum value, the two inequalities can be changed into equations
RELATED INFORMATIONS
- 1. A freight car is running on the straight road at the speed of V1 = 28.8km/h. Due to the wrong scheduling, a passenger car behind it is driving on the same road at the speed of V2 = 72km / h. at the distance of S0 = 600m, the driver of the passenger car immediately stops the truck. In order to avoid collision, at least how much speed should the passenger car speed up?
- 2. On the double track railway, there are two fast and slow trains, both 250m long, running in the same direction at the speed of 50km / h and 45km / h respectively How much time do they overtake? Use the system of linear equations with one variable to solve!
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- 5. A train runs at a constant speed through a 500m long tunnel, If it takes 30 seconds for the train to enter the tunnel and leave the tunnel completely, and the time for the whole train to be in the tunnel is 20 seconds, the length of the train can be calculated Using equation
- 6. A train is 200 meters long and has to pass through a 300 meter long tunnel. How many meters does the train travel from the front to the rear of the train?
- 7. Wang Xiaoya was riding on a 200m long train with a speed of 72km / h. from the window, she could see the train running head-on Wang Xiaoya was riding on a 200m long train running at a constant speed of 72km / h. from the window, she saw a 300m long freight train coming in front of her. The passing time was 10s, so she calculated the speed of the freight train
- 8. A train runs at a speed of 72km / h, and there is a tunnel directly in front of it. The train must whistle before entering the tunnel. The driver hears the echo reflected from the cliff at the tunnel entrance after 1.5s. How far is the driver from the tunnel when he hears the echo? (sound speed is 340m / s)
- 9. It takes 20s for a train to pass through a 300m tunnel. The tunnel light shines on the train for 10s. Ask the conductor
- 10. When a train enters a 300m long tunnel, it takes 20s from entering the tunnel to leaving completely. The time for the train to be completely in the tunnel is 10s
- 11. A 200m long train takes 45s to cross a 700 long bridge. What is the average speed of the train passing the bridge?
- 12. It takes 30 seconds for a train to cross the 430 meter long railway bridge. If the train speed doubles, It took 50 seconds for it to pass the 2180 meter iron bridge, so what's the length of the train
- 13. 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
- 14. How long does a 100 meter long train go through a 500 meter long cave at a speed of 72 km / h? Thank you
- 15. 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
- 16. When a train passes a bridge at 2160m per minute, the time for the whole train to be completely on the bridge is 2
- 17. For example, how long does it take for a 300m long train to pass through a 1600m tunnel at a speed of 36km / h? How long does the whole train spend in the tunnel?
- 18. How much speed does it take for a train to cross the railway bridge in 160m / S?
- 19. When a railway bridge is 1000m long and a train with length of AM passes through the bridge, the speed of the train is measured to be 1 & nbsp; min from the beginning to the end of the bridge______ ．
- 20. The train is 200 meters long. It takes 20 seconds to cross a 360 meter long bridge from the front to the rear. The train passes a 640 meter long bridge at the same speed A train with a body length of 200 meters passes through a 360 meter long bridge. It takes 20 seconds from the front of the train to the rear of the train. How long does it take for the train to pass through a 640 meter long tunnel at the same speed and enter from the front to the rear?