Train Definition and 638 Threads

A train of mass m=1.5 \cdot 10^5 kg is traveling at 40m/s when the brakes are applied and it decelerates steadily. The train travels a distance of 250m before coming to a halt. a) Calculate the deceleration of the train. b) Find the average braking force. I have tried to solve...

Using Einstein's train thought experiment, suppose a train is accellerating exponetially so that the engine remains forever ahead of a beam of light without it ever reaching the speed of light. V = c[ 1 - e^(-t)] for the train The light would approach the engine but never quite reach it...

An engineer is riding The El standing next to a bot holding a yo-yo which is hanging down. As the train starts to move, the boy looks at the engineer strangely as he whips out a protractor and measures a 4.19 degree angle between the string of the yo-yo and the vertical. The engineer quickly...

This subject has had other threads but I think specific answers to the questions that I will pose will clear up many points of confusion. To begin with, Einstein's train in section IX. of "Relativity" goes like this: Given a train of length AB proceeding from left to right at velocity v...

Homework Statement A bolt drops from the ceiling of a traincar which is acceleration northward at a rate of 2.5 m/s2. What is the acceleration of the bolt with respect a stationary train station. Homework Equations Seems more qualitative to me, but d = V1t + (1/2)at2 could be...

Homework Statement A given train can stop in t seconds when it is running at its maximum speed. The train driver sees a car stalled at an intersection that is d1 meters ahead of the train, and instantly pulls the brake starting while at its maximum speed. The train reaches the intersection u...

hi, can some one give me an outline of how to solve the following question? thanks Superman (mass=84.0 kg) must fly into a train (mass = 18079 kg) traveling at 75.0 km/hr to stop it. Calculate the minimum time Superman must take to stop the train, if the passengers experience an average...

So today in physics my teacher was talking about the bullet train that is in japan. SO this train is traveling at 190 miles an hour, and on this day there is no gravity and no air. a man walks to the back of the train and fires a bullet from the back. My teacher said that a person watching...

the frequency of radiation emitted when electron and positron are annihilated in the moving carriage is more than the the frequency of radiation emitted when the same experiment is done on railway platform .Is it not enough to decide that the motion of the train is real while platform motion is...

Homework Statement What power is required to push a train weighing 110,000 kilograms up an incline of 1 in 100 at 20 kilometers per hour, all frictional resistances being neglected? Homework Equations P = ΔE/ ΔT The Attempt at a Solution This is the only power equation we...

The train example discussing non-simultaneity that I'm sure most of you have heard of: However, wouldn't the passenger see the strikes of lightning at the same time? As she is in an inertial reference frame and is equi-distance from the front and back?

Dear forum, when I first read about special relativity I came up with this paradox. I went to the teacher who gave me the booklet but he couldn't answer my question. I'm quite confident that this forum is the place to answer my question: Does time goes slower or faster inside the...

A passenger train is traveling at 30 m/s when the engineer sees a freight train 336 m ahead of his train traveling in the same direction on the same track. The freight train is moving at a speed of 5.9 m/s. 1.If the reaction time of the engineer is 0.36 s, what is the minimum (constant) rate...

Hi I hope someone can help. I am working on a gear train with an electric motor which was burnt out and I'm trying to find the ratio and gear size without haveing to use a cutting torch to cut it up to get it out where I can work on it to measure the gear size. the gear on the motor (a) spins...

Brian, Amy and Stephanie are waiting at the train station. Each of the three is waiting for a different train. When they check the station clock, they realize that Amy is going to have to wait twice as long for her train as Brian will for his, while Stephanie will have to wait twice as long...

Homework Statement Superman must stop a 120-kmh train 150m to keep it from hitting a stalled car on the tracks. If the train's mass is 3.6 x 10^5 kg, how much force must he exert? Compare to the weight of the train (give as %). How much force does the train exert on Superman?" Homework...

This is my first time posting so it's nice to meet everyone! I'm not trained in physics, but lately I've been very interested in and reading a lot about both Relativity and Quantum Mechanics. With regard to relativity, I found the topic of relativity of simultaneity very interesting. The...

OKay i am a high school student making a model maglev train like the Inductrack design. I haven't started building yet but i know how I am going to make it and since i am using permanent magnets, the cart will not levitate right away. It will have wheels on the sides of the cart on rails to...

I was watching Mystery Science Theater 3k and they said something about a train a mile long. I decided to make up a problem to see if this was a rational length for a train by determining how much time it might take a train like that to pass. Train Length (L) = 1 mile (5280 feet) Velocity...

When an object is thrown by someone standing on top of a moving train, which variations of "frames of reference" would apply? (i.e. inertial, non-inertial, etc.) How would this principle work? (The object would go the same relative distance as it would if thrown from a person standing on...

Does anybody know why you hear the train wheel SCREECH when the train makes a curve?

I have been thinking recently about what a train driver actually does. It seems to me that he makes the train go and stop at the appropriate (and completely predictable) times. I don't doubt that there is slightly more to it than that, but I still find it very hard to imagine that there is...

http://img682.imageshack.us/img682/4396/movingtrain.jpg How do these observers line up in relation to each other when A' passes A? We know that from the train's reference frame B' will be adjacent to C and that from the embankment's frame C' will be adjacent to B, but as there is only one...

Homework Statement Fourier transform of scaled pulse train from -inf to +inf. Starting at 0 the first impulse is scaled at 2, the second impulse at 1 is scaled as 1, third at three scaled at 2, etc...Homework Equations Does my solution look correct?The Attempt at a Solution X(jw) =...

Homework Statement Engine: 100 tonnes, with 1,000N frictional force Train: 400 tonnes, with 20,000N frictional force Speed = 80km/hour Engine is exerting a power of 4000kW Find the tension in the couplings between train and engine The Attempt at a Solution I'm not sure where to...

Two/Three-parter: First, a very basic physics question - if you could just step onto a speeding train (pretending that the force of such an act wouldn't break every bone in your body), are you accelerating to the speed of the train, or did your speed just suddenly increase? The underlying...

Homework Statement A train is traveling up a 3.73 degrees incline at a speed of 3.25 m/s when the last car breaks free and begins to coast without friction. a) How long does it take for the last car to come to rest momentarily? b) How far did the last car travel before momentarily coming to...

The SuperConducting Train The Superconducting train principle, I've seen this video on Geekologie and then followed the link to Youtube. The thing is i don't understand the physics behind this, and would love for someone to be able to explain how its working, especially the contents of the...

If anyone could help me with these two questions that would be great. 1.A freight train has a mass of 1.20E+7 kg. If the locomotive can exert a constant pull of 8.03E+5 N, how long does it take to increase the speed of the train from rest to 70.6 km/hr? 2.A football punter kicks a...

Homework Statement A person is standing on a train that is moving 200 km/h to the right. The person fires a bullet that travels 200 km/h opposite the direction of the train's movement. How fast is the bullet moving according to the shooter's perspective (assuming there is no gravity, resistive...

A high speed train traveling at 84 kph locks its wheels and skids 84 meters before coming to a complete stop. If the rate of slowing down is constant, how many seconds will it take for the train to come to a complete stop?

This concerns a debate I'm having with two friends of mine, hope someone here can help. You have a train traveling at 100km/h. Inside the train there is a car traveling at 100km/h. Inside the car is a jogger running at 20km/h. Suddenly the train and car stop and the jogger is thrown...

Homework Statement Two long trains carrying coal are traveling in the same direction side by side on separate tracks. One train is moving at 40 ft/sec and the other at 50 ft/sec. In each coal car a man is shoveling coal and pitching it across to the neighboring train. The rate of coal...

One of the scenarios that I've come across while reading about special relativity is the scenario of a person riding on a train undergoing constant velocity motion, such that the person in a train car with all windows drawn is unaware that their train car is moving at all. The car is not...

1. A red train traveling at 72 km/h and a green train traveling at 144 km/h are headed toward each other along a straight, level track. When they are 950 m apart, each engineer sees the other’s train and applies the brakes. The brakes slow each train at the rate of 1.0 m/s2. Is there a...

Homework Statement I'm having a tough time with relativity, and I thought I'd try this problem to see if I understood the topic very well. Let's consider a train moving at 0.65c along a straight track. Its headlight produces a beam with an angular spread of 60 degrees. If you astanding...

Homework Statement A locomotive accelerates a 25-car train along a level track. Each car has a mass of 6.8e104 kg and is suject to a drag force f = 250v, where v is the speed in m/s and the force f is in N. At the instant when the speed of the train is 44 km/h, the acceleration is 0.20 m/s2...

Homework Statement A bolt drops from the ceiling of a train car that is accelerating northward at a rate of 3.50 m/s2. (a) What is the acceleration of the bolt relative to the train car? (b) What is the acceleration of the bolt relative to the Earth? The Attempt at a Solution (a)10.4...

Fly in a train! Hey guys, i was wondering what happens if an object is suspended in mid air inside a moving train? Why doesn't the object just fly back to the back of the train when the train starts moving? I mean it has got no contact with the train so it will not have the velocity of the...

It seems there is usually no mention of "redshift" when train thought experiment is used to teach relativity. Is there a reason for not bringing redshift (blueshift) into the experiment?

Hey, I have managed to make model maglev train that uses permanent magnets and metals for levitation. It levitates all right but i need ideas to propel it forward. I have attached a picture showing how the model works. Please reply if you have any ideas. Thanks.

train moving at velocity "v" relative to earth My question is a basic one so patience would be appreciated =) Say we have a train moving at velocity "v" relative to the Earth. A man standing inside shoots a bullet at velocity "w" relative to the train's motion. The bullet should thus...

Howdy! In the middle of reading "The Fabric of the Cosmos" by some MIT physicist or something. I'll present the problem differently than he did because i like my presentation better and it doesn't change the meaning of the problem. There is, on a moving train, a pile of gunpowder. On...

Homework Statement A toy train moves along the track at 9.0m/s. When the power is turned off, the train comes to a stop in 6.0s. The net force on friction acting on the train to stop it is Homework Equations F=ma The Attempt at a Solution how do i find mass and acceleration so...

George took a train at station X with the intention of going to Station Y (which is located 8 kilometers from station X). At the precise instant that the train started leaving station X, the minute hand of his 12 hour analog wristwatch was located precisely on a minute mark. George looked at...

Homework Statement A train consists of of 50 cars, each of which has a mass of 6800 kg. The train's acceleration = 0.08 m/s(squared). Ignore friction and determine the tension in the coupling (a) between the 30th and 31st cars and (b) between the 49th and 50th cars. Homework Equations Net...

If the light clock was on top of the train, it wouldn't be in a inertial system. If a table tennis game was played inside the train, the ball would move as if played on the platform. But it wouldn't be possible ontop of the train. Does the light react the similarly to a table-tennis ball or is a...

What do you guys think would be the best way to trip a camera so that it goes off only for when a train is passing through it? Sorry I can't get anymore specific than that. I was thinking laser tripping device but was wondering if there is anything out there that maybe used that ya'll might...

a moving emitter passes point A traveling at .5 c and emits one photon along the direction of travel. At that same instant a freight train traveling at .5 c passes point A in the opposite direction. Question 1 - two seconds later where is the moving emitter with respect to point A? Question...

I've remembered in bits and pieces a thought experiment that I can't get a grasp on what was suppose to be explained and I was wondering if anyone happens to know what this is. Supposedly this was a famous thought experiment or osmething and I must have been told of it years ago, possibly even...