![](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>)
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
Fine! A certain length of time or a certain distance is longer than the time used
The speed of an aircraft is 20 times that of a car, while the speed of a bicycle is 1 / 5 of that of a car, and the speed of walking is 1 / 2 of that of a bicycle. If the speed of a car is a km / h, the speed of an aircraft is () km / h, the speed of a bicycle is () km / h, and the speed of walking is () km / h
20a 1/5a 1/10a
Someone travels for 22 days by train, 1 / 3 by car and 1 / 4 by bike. The speed of bicycle is 1 / 8 of that of train and 1 / 4 of that of car, Supplementary question: how many days by train, car and bike?
If x days are taken by train, y days by car and Z days by bike, and the total distance is s, then
X+Y+Z=22 ,8/Z=1/X=2/Y,
The solution is x = 2
Y=4
Z=16
A: 2 days by train, 4 days by car and 16 days by bike
What is the speed of walking, bicycle and car
People usually walk at a speed of 4 ~ 7 km / h. if they walk fast, they may walk 10 km / h. if they walk fast, they can reach 15 km / h
The speed of ordinary bicycles is 16-18km / h, and if you ride faster, it will be 20km / h
The speed of the car is not easy to talk about. It can range from zero to hundreds of hours
The normal speed of the train from station a to station B is 60 km / h. a train left station a 5 minutes late for some reason. The driver increased the speed to 72 km / h. as a result, it arrived at station B on time. What is the distance between the two stations? What is the normal travel time of the train from a to B? Answer questions in a scientific way,
The normal time is h hours and the distance between the two stations is s km 1) 60H = s delay time: 5 / 60 = 1 / 12 hours 2) 72 (h-1 / 12) = S1), 2) the formula 72 (h-1 / 12) = 60h72h-6 = 60h72h-60h = 612h = 6h = 0.5 (H) 60H = s60x0.5 = S30 = s, that is, s = 30 (km), so the normal time is 0.5 hours and the two stations
The normal running speed of the train from station a to station B is 60 km / h The normal running speed of the train from station a to station B is 60 km / h. for some reason, an existing train left station a 5 minutes late, and the driver raised the speed to 72 km / h. as a result, it just arrived at station B on time. What is the distance between stations a and B?
60*（72*(1/12)/（72-60））=30km
RELATED INFORMATIONS
- 1. 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
- 2. 2 / 1 of the car speed is equivalent to the train speed, and the unit "1" is（
- 3. Ask a simple question about finding indefinite integral To find the indefinite integral of SiNx to the third power DX, the book says that x in DX should be regarded as cosx. How can this be changed in the past?
- 4. An iron bridge is 1000 meters long. A train passes through the bridge. It is measured that it takes 1 minute for the train to get on the bridge and 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 to get off the bridge). What is the speed and length of the train?
- 5. There is a railway bridge with a length of 1000 meters. A train passes through the bridge. It is measured that it takes 120 seconds for the train to get on the bridge and get off the bridge completely. The time for the whole train to be completely on the bridge is 80 seconds. What are the speed and length of the train respectively?
- 6. Nanjing Yangtze River Bridge is 1600m long, and a 250m long train passes through the main bridge at a constant speed for 3min5s. Calculate the time when the train runs on the main bridge The format is 1. Known 2. Ask 3.4. Answer
- 7. Some students took the power train to travel. When the train accelerated evenly on a straight track, one student proposed, "can we use the equipment around us to measure the acceleration of the train?" many students participated in the measurement. The measurement process was as follows: they looked out of the window every 100m While recording the time with a watch, they observed that the time interval from the first landmark to the second landmark is 5S, and the time interval from the first landmark to the third landmark is 9s. Please find out according to their measurement: (1) Acceleration of train; (2) The speed at which they reached the third sign
- 8. What is the indefinite integral of 1 + x ^ 2 under the root sign? It is necessary to explain the process or method
- 9. The car runs 60 kilometers per hour and the train runs 75 kilometers per hour. How many percent faster is the train than the car?
- 10. As shown in the figure, a railway bridge is 400m long. A person walks on the bridge. When he walks 190m away from the bridge head in front, he finds a train coming in the face. The train speed is 40m / s and the train is 800m away from the bridge head in front. How fast can the person run at least to leave the railway bridge safely?
- 11. 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
- 12. 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?
- 13. Derivation y = [arcsin (2 / x)] square
- 14. Derivative method of compound function
- 15. Trigonometric function inverse trigonometric function multiplication cosarcsinx= sinarccosx= sinarctanx= cosarctanx=
- 16. (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
- 17. The simplest problem of inverse trigonometric function It's tan θ= b. Expressed by inverse trigonometric function θ How much is it
- 18. 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?
- 19. 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?
- 20. 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?