![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
If a 200m long light rail train passes through a 2.8km overpass at a speed of 15m / s, how long does it take for the train to get on the bridge and completely pass the bridge?
The distance of the train completely passing the bridge:
S = l bridge + L vehicle = 200m + 2.8 × 103m=3000m，
Time when the train completely passes the bridge:
t=s
t=3000m
15m/s=200s．
A: it took the train 200s to cross the bridge
If a 300 meter long light rail train passes through a 2.7 km overpass at a speed of 10 meters per second, how long does it take for the train to get on the bridge and completely pass the bridge?
2.7 km = 2700 M
(2700+300)÷10
=3000÷10
=300 seconds
If a 200m long light rail train passes through a 2.8km overpass at a speed of 15m / s, how long does it take for the train to get on the bridge and completely pass the bridge?
The distance of the train completely passing the bridge:
S = l bridge + L vehicle = 200m + 2.8 × 103m=3000m，
Time when the train completely passes the bridge:
t=s
t=3000m
15m/s=200s．
A: it took the train 200s to cross the bridge
A bridge is 1.6km long, and a 200m long train passes through the bridge at the speed of 15m / s. how long does it take for the train to completely pass through the bridge?
（1600+200）/15m/s=120
A bridge is 1.6km long, and a 200m long train passes through the bridge at the speed of 15m / s. how long does it take for the train to completely pass through the bridge?
Distance of train crossing the bridge: S = 1600m + 200m = 1800m,
From the velocity formula: v = s
T it can be seen that the time when the train crosses the bridge:
t=s
v=1800m
15m/s=120s；
A: the time required for the train to completely pass the bridge is 120s
A 360m long train passes through a 1800m long tunnel at a constant speed. It is measured that it takes 108s for the train to pass through the tunnel completely. Find: (1) The running speed of the train (unit: M / s), which is km / h; (2) The time taken by the locomotive from just entering the tunnel to just leaving the tunnel; (3) The time when the train runs in the tunnel
(1) The distance of the train completely passing through the tunnel: S1 = l tunnel + L vehicle = 1800m + 360m = 2160m, speed v = s1t1 = 2160m108s = 20m / S = 72km / h; (2) The time taken by the locomotive from just entering the tunnel to just leaving the tunnel is the time taken by the train to completely pass through the tunnel, i.e. 108s; (3) The train is all
RELATED INFORMATIONS
- 1. Calculation: a train passes through a 1800m long tunnel at a uniform speed of 20m / s. It is measured that the time required for the train to completely pass through the tunnel is 108s. Calculate: (1) What is the length of the train? (2) How long did the train run in the tunnel?
- 2. The simplest problem of inverse trigonometric function It's tan θ= b. Expressed by inverse trigonometric function θ How much is it
- 3. (Mathematics) the problem of finding the inverse function of a trigonometric function If cosx = - 1 / 3, X ∈ (π / 2, π), then x=_______ The answer is π - arccos (1 / 3), but I don't know how it came out. Please write down the steps
- 4. Trigonometric function inverse trigonometric function multiplication cosarcsinx= sinarccosx= sinarctanx= cosarctanx=
- 5. Derivative method of compound function
- 6. Derivation y = [arcsin (2 / x)] square
- 7. 1: Known f (x) = 2x ³- 6X ²+ A (a is a constant) has a minimum value of 5 on [- 1.2], so what is the maximum value in this interval? 2：COSASINC+COSCSINA/SINASINC =SIN(A+B)/SIN ² B =1/SINB How did you get it?
- 8. A train is 200m long and it takes 2min to pass through a 1000m long tunnel. How long does it take to pass through a 3.4km long bridge at this speed
- 9. Generally speaking, the speed of cars is faster than that of bicycles, and the speed of bicycles is faster than that of people. When judging the speed of cars, bicycles and people, is it determined by the length of exercise distance or the amount of exercise time? Give your opinion
- 10. The normal running speed of the train from station a to station B is 60km / h. There is a train leaving from station A. due to the delay of 10s, the driver raised the speed The normal running speed of the train from station a to station B is 60km / h. There is a train leaving from station A. due to the delay of 10s, the driver increased the speed to 72km / h and just arrived at station B on time. Calculate the distance between station a and station B and the normal running time
- 11. A 200 meter long train passes a 1 kilometer long bridge at the speed of 40 kilometers per hour. How long does the train pass the bridge?
- 12. A train advances at the speed of 20m / s and whistles 1800m away from a tunnel entrance. Q: when the driver hears the echo, how far is the locomotive from the tunnel entrance
- 13. Proof of differential formula of inverse trigonometric function Complete steps to prove d (arctan x) / DX = 1 / (1 + x ^ 2) The two formulas cos ^ 2 y + sin ^ 2 y = 1 and 1 + Tan ^ 2 y = sec ^ 2 y can be used
- 14. The following indefinite integrals are obtained by the first type of substitution method (approximate differentiation method) or the second type of substitution method: 1）∫dx/[x*(x^6+4)]; (1/24)*ln[x^6/(x^6+4)]+c; 2) ∫cosxcos(x/2)dx ; : (1/3)sin(3x/2)+sin(x/2)+c; 3) ∫tan^3secxdx; : (1/3)(secx)^3-secx+c; 4 ∫dx/[x√(x^2-1)]; : arccos(1/x)+c; The answer has been given, please give the process. Do not require all answers, solve one by one
- 15. Given log (12) 27 = a, find the value of LG (2) / LG (3)
- 16. A train moved forward at the speed of 38m / s and whistled 600m away from a tunnel entrance. When the driver heard the echo, how far was the locomotive from the tunnel entrance? (the sound velocity is 340m / s) (do not set the unknown number method to solve, but answer in the way of known, seek and answer.)
- 17. From the perspective of mechanical stress analysis, how to explain that the rotating tire rolls forward after the car starts? Or how to analyze the relationship between the tire and the ground Stress condition?
- 18. As shown in the figure, if the length, width and height of the elevator are 1.2m, 1.2m and 2.1m respectively, what is the maximum length of the bamboo pole that can be put into the elevator?
- 19. What is the difference between translation and distance? Please give an example
- 20. Examples of sliding friction, rolling friction and static friction in life