Train Definition and 650 Threads

  1. S

    Train Collision Stopping distance Problem

    Homework Statement Two trains, one traveling at 74.00 km/h and the other at 148.00 km/h, are headed toward one another along a straight, level track. When they are 938 m apart, each engineer sees the other's train and applies the brakes. The brakes decelerate each train at the rate of 1.0...
  2. C

    Train Braking Distance Calculation

    Hi. I would really appreciate it if someone could please help me with the following M1 level kinematics question as I am really stuck. The brakes of a train can produce a retardation of 1.7 m/s^2. If the train is traveling at 100 km/h and applies its brakes what distance does it travel...
  3. B

    Train pulling caboose - forces and friction

    Homework Statement A 2.7 kg toy locomotive is pulling a 1.2 kg caboose. The frictional force of the track on the caboose is 0.48 N backward along the track. If the train is accelerating forward at 2.7 m/s2, what is the magnitude of the force exerted by the locomotive on the caboose...
  4. camilus

    The fly and train math problem

    Ok so the problem: 2 trains are 100 miles apart traveling towards each other on the same track. Each train tavels at 10 miles per hour. A fly leaves the first train heading towards the second train the instant they are 100 miles apart. The fly travels at 30 miles per hour (relative to the...
  5. S

    What is a good way to train for the USAPhO?

    What is a good way to train for the USAPhO? I know doing a lot of problems is KEY, but I was wondering along the lines of the best books. I have Halliday and Resnick as well as University Physics (don't ask why >_>) so I was wondering if doing these books is enough to become a semi finalist...
  6. B

    Equal Forces - Bullet and train (opposite directions)

    Hi I've been having an argument with a few friends about a theory of mine (based on what i can remember from my physics lessons and common sense (i think lol). My theory is this. There is a train traveling at 100mph in one direction There is a man with a gun standing at the back of the...
  7. N

    Fourier transform of a modified impulse train

    I need to find the Fourier Transform (FT) of: x(t)=\sum^{\infty}_{n=-\infty}((-1)^{n}\delta(t-nT)) Not really sure how to solve this problem, so any help will be appreciated. Also, if you guys know a good reference for non-uniform sampling and reconstruction, please post it.
  8. M

    How Long Does Each Stage of a Tube Train Journey Take?

    HELP! Answer pls ^^ a tube train covers 432m from rest to rest in 1 minute. It first accelerates 1/3 m/s2 then goes uniformly and finally retards at 1 m/s2. Find the time taken in each of the three stages of the journey. PLEASE HELP ^^ CONFUSED ON WHAT FORMULA AND HOW TY...
  9. S

    What is the combined speed of linked model train cars with different masses?

    A model-train car of mass 230 g traveling with a speed of 0.50 m/s links up with another car of mass 430 g that is initially at rest. What is the speed of the cars immediately after they have linked together?
  10. WolfOfTheSteps

    Fourier Transform of a Modified Impulse Train

    I hope this is OK to post here. I thought it would be better here than in the math questions forum, since you are EEs, and probably have more experience dealing with things related to the delta function. Problem Let \hat{x}(t) = \sum_{k=-\infty}^{\infty}\delta(t-2k). Now let x(t) =...
  11. B

    How long does it take for the train to stop moving?

    Homework Statement a train is traveling down a straight track at 20m/s when the engineer applies the brakes resulting in an acceleration of -1.0m/s^2 as long as the train is in motion. how far does the train move durin g a 40 second time interval starting at the instant the brakes are applied...
  12. P

    How Is the Beat Frequency Calculated When a Train Approaches a Station?

    Homework Statement A radio played on a moving train has frequency of 85 Hz. A second radio played at train station is at rest. What is the beat frequency heard if train approaches the station at 10 m/s? Homework Equations f' = [f \ (1-vsource/vsound) I used this equation because the...
  13. J

    Inclined ramp inside an accelerating train

    Hello, I have a question for homework. The question reads: A body of mass m=4.8 kg is standing on a ramp inclined in an angle of α=12 degrees. The static friction coeficient between the ramp and the body is μ=0.24. The ramp, which is inclined to the left, is in a train, which accelerates to...
  14. edward

    Thomas The Train and Friends Toys Recalled

    The toys apparently have lead in the paint. I have a feeling that the list below from the Consumer Product Safety Commission is going to grow. I bought these for my grandson from "The Learning Curve". DAMN They should have been covered in gold for what they cost...
  15. S

    Maglev Train Engineering Report: Braking Systems

    Hey guys could some one give me a link to an engineering report on maglev trains. I am doing an assessment on braking systems and have chosen magnetic brakes from the maglev train. So i need a full on complex engineering report on them and info on Hydro-Aire Brakes, Aerodynamic Brakes, Linear...
  16. J

    Light shone in a train bouncing off mirrors

    I have a question about a thought experiment I read about. I think the question or a similar was asked, and I'm sure others have asked this question, but I'm asking it in this way so it can be answered through the framework of my question. The framework of how I'm understanding it, and so that...
  17. G

    How does relative motion affect speed calculations?

    OK This maybe a dumb question but we have some debate on this question here at my work. No one here is a physics pro. :) Here's the question. If a train is moving at 5mph and you are moving tward the back of the train at 2 mph. How fast are you going? Now I think the answere is 2 mph do to...
  18. E

    Train whistle frequency difference in approaching and receding

    Homework Statement Whistle frequency is 595 Hz for the train and sounds higher or lower depending on whether it approaches it or recedes. Calculate the difference in frequency between approaching and receding train whistle for a train moving at a speed of 105 km/h. Speed of sound is 340 m/s...
  19. J

    Why Do Tilting Trains Reduce Side Forces on Banked Curves?

    1. Tilting trains such as the Acela, which runs from Washinton to new York to Boston, are designed to travel safely at high speeds on curved sections of track which were built for slower, conventional trains. As it enters a curve, each car is tilted by hydraulic actuators mounted on its trucks...
  20. F

    About a bee flying inside a moving train

    I have some questions which i can't seem to answer and understand. Here goes: Imagine a bee flying inside a moving train moving at a constant velocity in one particular direction. the bee is flying in mid-air and is not in contact with any of the train parts. qns 1: does the bee need to...
  21. J

    Riding the Train -Vecotrs & components

    Riding the Train --Vecotrs & components A passenger train is cruising directly to the north at 16.0 mi/hr. what are the speed and (numerical) direction of a passenger with respect to the ground on this train, if he now walks east-ward at 5.4 mi/hr? ---Compass heading in degrees: N=0, E=90...
  22. A

    Calculating Time for Train to Stop Moving Up Inclined Mine

    An engine is used to pull a train of 2 cars out of a mine. The floor of themine slopes upward at an angle of 30 degrees. Each car has a mass of 10^4 kg and travels without friction. The engine can exert a max force of 1.5 * 10^5 N if the engineer trttles back so that the force exerted by the...
  23. G

    What is the final velocity of the five-car train after a series of collisions?

    Homework Statement Three identical train cars, coupled together, are rolling east at 3.97 m/s. A fourth car traveling east at 4.59 m/s catches up with the three and couples to make a four-car train. A moment later, the train cars hit a fifth car that was at rest on the tracks, and it couples...
  24. J

    Need help w/ Acceleration of a Freight Train problem

    Question: A freight train has a speed of 29.8 m/s at a given instant and 9.2 seconds later its speed is 26.2 m/s. train's acceleration is -3.91×10-1 m/s^2 What additional time would be necessary to bring the train to a complete stop, if it continues to slow at the rate given? What...
  25. D

    Uniform Circular Motion of a train

    I was wondering if someone could help me figure out what formulas to use solving this problem. My professor gave me the answer (as a way to check our answers) : 1.48 m/s^2 inward and 29.9 degrees backward The problem is: A train slows down as it rounds a sharp horizontal turn slowing from...
  26. M

    Calculating Frequency of Train Whistle for Approaching Passenger

    A train is traveling at 30.0 m/s relative to the ground in still air. The frequency of the note emitted by the train whistle is 262 Hz. a. What frequency (fapproach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first...
  27. B

    Friction on an accelerating train

    I have a question for homework, and this is a high school physics class. The question reads: Suppose that you are standing on a train accelerating at 2.0m/s^2. What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide? I've drawn a free...
  28. T

    Jumping inside a moving train

    Why when you jump inside a moving train you land exactly in the same place, instead of landing closer to the tail of the train? I know it a stupid question but I am not able to find what physical law applies in this case. Has it something to do with momentum cancellation? (I remember the...
  29. D

    Temporal distortion along train DURING Acceleration

    During acceleration, will the train's rear clock appear to tick faster than the train's front clock from stationary frame of reference ? I am asking because i don't see how else the train's rear clock would read farther into the future than the train front clock. Either the rear clock...
  30. D

    Temporal distortion of a moving train

    Hi i have a question about how time is distorted along the length of a train moving at near light speeds. Will the front carriage be farther foward in time than the rear carriage from stationary frame of reference? or the otherway round? Assume that the front and rear sections had clocks...
  31. P

    Help Needed: Solving Train Acceleration Problem

    hello I'm having some trouble with the following problem: train B leaves point A at 8am to point B located 30 km straight a head. the train has constant acceleration a=0.05 m/sec^2 now train B leaves point B 5 minutes before train A gets there,what is the acceleration of train B in...
  32. S

    How Is Tension Calculated Between Train Cars During Acceleration?

    A train consists of 50 cars, each of which has a mass of 6.6*10^3 kg. The train has an acceleration of 6.0*10^-2 m/s2. Ignore friction and determine the tension in the coupling at the following places. A)between the 30th and 31st cars B)between the 49th and 50th cars I know f=ma that's...
  33. F

    A freight train has a mass of 4.5*10^7 kg

    A freight train has a mass of 4.5*10^7 kg. If the locomotive can exert a constant pull of 15*10^5 N, how long would it take to increase the speed of the train from rest to 85 km/h? I know u need to use F=ma but how do i find time
  34. C

    How can I train data separated into subsets

    Hi all, Maybe i shud put it this way. Suppose I want to perform training on part of the data and leave the rest for testing. the training set is separated into subsets whereby I train one subset first, and use its weights and biases as weights to the next subset and so on. Then how to I write...
  35. Ookke

    A relativity problem (train & platform)

    This is a "paradox-type" relativity problem that I cannot figure out. Hope it's OK to post this here. Sorry for English errors, it's not my native language. Here it goes: Railway. Platform (1 km) by side of it. Train (100m). Train approaches platform very high velocity, so that (in train's...
  36. H

    Velocity and acceleration of a train

    A train travels due south at 60 m/s. It reverses its direction and travels due north at 60 m/s. What is the change in velocity of the train? Whats the average acceleration if it took 2 sec. to reverse.
  37. O

    How Do You Calculate Constant Deceleration to Prevent a Train Collision?

    Say a locomotive at a constant 18 mi/h comes onto a track (from some other track) that has a passenger train att 100 mi/h on it. At the instant the train is 0.42 miles away from the locomotive, it starts to decelerate. What is the resulting constant acceleration that is needed to just avoid a...
  38. Y

    Solving the Puzzle: Train and Car Speeds

    A train is moving parallel and adjaceent to a highway with a constant speed of 33 m/s, initially a car is 37 m behind the train, traveling in the same direction as the train at 47 m/s and accelerating at 5 m/s^2. What is the speed of the car just as it passes the train? Answer in units of m/s...
  39. W

    How Does Centrifugal Force Affect Weight on a Curved Train Track?

    A train is running smoothly along a curved track at the rate of 50 m/s. A passenger standing on a set of scales observes that his weight is 10% greater than when the train is at rest. The track is banked so that the force acting on the passenger is normal to the floor of the train. What is the...
  40. R

    Constant Acceleration of a train

    The question is A Train pulls away froma station with a constant acceleration of .4m/s^2. A passenger arrives at the track 6.0s after the end of the train has passed the very same point. what is the slowest constant speed at which she can run and catch the train? I am rather confused on...
  41. D

    Tennis Ball Collide With Train Prob.

    hi all, the qns is when a tennis ball collide with a train, can the ball stop the train for a split sec, since during collision, the ball have to change direction so velocity at some point in time is equal to zero. Being at V= 0 for that split sec, and since the ball is in contact with the...
  42. W

    Train Blows Away Person: Is It True?

    Is it true that a somewhat fast (say 150 km/h) train with a flat-headed locomotive pushes so much air in front of it that a person on the track would not (at first) be hit but blown away?
  43. T

    Does a tennis ball stop a train if it hits it?

    Hi, If I were to throw a tennis ball at an oncoming train would the ball stop the train momentarily while the ball changes direction? Due to the conservation of energy! Regards Tom
  44. W

    Radial and Tangential Acceleration of a train

    Hello everyone, I have two questions about this problem: "A train slows down as it rounds a sharp horizontal turn, slowing from 90.0 km/h to 50.0 km/h in the 15. s(seconds) that it takes to round the bend. The radius of the curve is 150 m. Compute the acceleration at the moment the train...
  45. L

    Mysterious Phenomenon: Throwing Paper out a Train Window

    hey, is it possible, that when you throw a piece of a newspaper true the window of a train, the paper enters back at the following window ? thx laurens
  46. B

    Rain in a train wagon - speed, momentum and KE

    We have a physics exam tomorrow, and have been presented with a previous exam for practice. One of the assignments have puzzled us quite a bit. Here goes: Rain in a train wagon Consider a train wagon whose upper part is a lidless box. The train wagon moves without friction. There is water in...
  47. himanshu121

    What are the key factors affecting high speed train aerodynamics?

    Hi, can anyone please tell me any good book on the subject, even any research paper will do, we are actually doing summer project in which we are estimating the drag coefficient on the bluff body like train Coach, using commercial softwares like Fluent n Gambit.Please if anyone has the info...
  48. Y

    Man Running on a Train: Clocks and Velocity

    A train travels at a high speed v wrt the earth. A runner on the train sprints toward the back of the train at velocity v wrt the train. Clocks on the train should run slow compared to Earth clocks. The runner's clock should run slow compared to the train clock. Therefore the runner's...
  49. marcus

    't Hooft: an original train of thought

    On page 3 of this new paper of Gerard 't Hooft it is written: This paper was written while these facts were being discovered, so that it represents an original train of thought, which may actually be useful for the reader. Here is a paper that contemplates a deterministic basis for Quantum...
  50. J

    Can a Man Catch a Constantly Accelerating Train?

    :confused: Please help with this problem. A train moves from rest with const accel. a in a straight line. A man at distance b behind the train chases it with const. speed V. Show he can catch it if V^2 >2ab, and find when he does so. I have found formulas for distance traveled for each and...
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