Train Definition and 638 Threads

Can someone answer this question? If I throw a ball forward and another one backward (opposite to the train's movement) in a moving train, do both balls land at an equal distance from the thrower? I suspect throwing a ball forward is the same as throwing it in a motionless train but what about...

I am reading up on the special theory of relativity, and watched a video. In the video we have a train moving at ½ c towards a station, where an observer is waiting. The train's headlamp is on. How would the lamp's light appear to the observer? I was thinking that it¨'d appear to the observer...

Hello all I am trying to work out the forces involved of a moving train around a curve traveling at a constant speed. I have the following:- The image on the left is a cross section of a train traveling around a curve, you can think of the train moving away from you. The image on the right...

Let's say there is a train moving at 50 mph on the moon on a flat surface (say it's a perfect vacuum) and you are on the last cart where you throw a ball out the rear in the opposite direction the train is moving (directly away from it, parallel to the ground). The ball thrown is also...

A train is traveling around the Earth at just under light speed. Light would circle the Earth around 7 times per second so let's say this train cricles the Earth 6 times per second. There is a physical ticker on the track of the train that records revolutions. Each time the train makes one...

Summary: Consider a train carriage rolling along a curve that forms a left turn on the track. The carriage speed is directed along the y-axis (into the plane of the paper) in the figure. The trolley will have a tendency to curl in the curve in the specified direction. A flywheel is inserted...

I'm attempting to train and interact with a quantum dog named Rusty. Any and all suggestions are or aren't appreciated.

Hello, I was wondering if anyone could set up and solve a classic train in a tunnel paradox from special relativity with unique values for multiple observers including time space diagrams. Thanks

Summary: how can a train traveling at light speed, travel at two different speeds being the same train, depending upon whether you are on the train platform or in the train You say good bye to your friend at the train station. You get into train that will travel at just under light speed...

Hi, I have been reading and watching a lot of physics lately but I have come across this problem. I have the basics of special relativity down, and it all seems clear to me. This is not in question to me. For example, I am reading a book on string theory by Brain Greene, and in it he covers...

So I got this from an article on wikipedia that covers Einstein's train thought experiment: A popular picture for understanding this idea is provided by a thought experiment similar to those suggested by Daniel Frost Comstock in 1910[13] and Einstein in 1917.[14][12] It also consists of one...

Hi guys, I have read about these twins where one of them stayed on the Earth and the other traveled with a rocket. So I thought about the other case where a person stays on the trains station and the train is passing by with a near speed of light - if the guy in the train drops a ball on the...

Homework Statement A passenger train is traveling at 29ms^-1 and a freight train is traveling 360m ahead of it at 6ms^-1 in the same direction on the same track. The driver of the passenger train has a reaction time of 0.4s before he starts decelerating. What is the minimum deceleration to...

Homework Statement When a train traveling at 161 km/h rounds a bend, the engineer sees that a locomotive has entered onto the track from the side and is a distance D=676m ahead. The locomotive is moving at 29 km/h. The engineer of the high speed train immediately applies the brakes. What must...

Every time I take a train I sort of think about this, so the electrified overhead wire (DC or AC) and the rails form a transmission line and the train is a load that moves along the transmission line. Let's talk about the DC case as it seems more simple, so when the train is at or near a...

Question from non-physicist. Hope there is a simple answer. In Einstein's thought experiment with moving train and embankment: If there is an observer in the middle of one of the train cars and one light beam is flashed from inside each side of the car (same location on each sides) towards the...

Homework Statement [/B] A train stands in the middle of a rotating disk with an initial angular velocity of $\omega_i$. The mass of the train is m and the moment of inertia of the train-disk is I. At one point the train departs on a straight track to a distance R from the disk's centre. (R...

I am currently in grade 12, and for a physics project (a huge project, which gets assigned to you at the start of the semester and needs to be completed just before exams. You think up your project, make a proposal for it and you prove your hypothesis to be right after a presentation and lab...

[Moderator's note: Spin off from previous thread: https://www.physicsforums.com/threads/is-the-andromeda-paradox-accepted-in-physics.960861/] There's just one thing I don't understand about all this, Einstein's train thought experiment. It basically states that an observer in a train moving...

Homework Statement There is a train of length d and speed v. It is heading towards a hill with height h and length of each side l. What velocity requirement must be met so that the train can go up and down the hill? Homework Equations Ek=m⋅v2/2 Ep=m⋅g⋅h The Attempt at a Solution I'm basically...

Homework Statement A UTA Trax train engine can apply 96050 Newtons and locomotive has a mass of 1750 kg. The passenger car has a mass of 949 kg. (A) If the train accelerates at a rate of 1.29 m/s/s, how much friction is present in the passenger car? (Assume the locomotive moves...

I have been set the following question in my assignment and I have answered all parts with the exception of:- (d) Determine an equation for the efficiency of the gear train in terms of the load (torque) on shaft 2 (all other factors remaining constant). I am struggling here and would appreciate...

Homework Statement A train 400 m long is moving on a straight track with a speed of 21.6m/s. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 5.0m/s. Assuming constant acceleration, determine how long the train blocked the crossing...

Property of walking is a constant contact with the surface (base of the train). Property of running is NOT a constant contact with the surface (base of the train). When walking at the same speed we should expect the same result for our hypothetical walker to walk across certain distance (within...

Please move this if it belongs to other subforums. So i thought about some other stuff and then somehow this idea appeared to me, now according to physics it is impossible to communicate information faster than the speed of light through vacuum which is "c". So for any two bodies moving in...

Hi there again, I am trying to correctly calculate the tractive effort pf a train, currently i do this: Power/speedMpS = TractiveEffort I got that from here. But it doesn't provide realistic values, so i am wondering, what is the correct way of calculating tractive effort of a train? Thanks

Hi there again, I have been wondering why train simulators(and trains themself) have a kW specification, AND a maximum force indication. If I would calculate the speed of a train using some formula, then where is the power value used for? Does it have something to do? Or is only the maximum...

Hi there, So I asked a question here how I would calculate the air drag and the wheel drag of a train and I got an answer that made me very happy. Unfortunately i don't know where i could find the coefficient values required for the formulas. So i am wondering if someone knows where i can find...

Hi there, I am new here so please don't be too hard on me yet and move this post if i placed it in the wrong forum. I am developing a little experiment game and i want the train to drive using real physics, but I am really bad at physics. So my question is is how do I calculate the friction of...

a DC electric train or tram uses a single overhead wire unlike it's AC counterparts like trolleys which use two, so if there is only a single overhead wire I assume that the return wire or let's call it ground for the electric DC train are the rails correct? Does this mean that it is important...

Homework Statement What is the maximum acceleration the train can achieve? Engine effect=6500kW μ(Friction Coefficient (between rails and wheels))=0.45 g=9.82N/kg m(Train weight)=120,000kg α=0 Homework Equations Fμ=Fn*μ Fn=cos(α)*m*g a=F/m The Attempt at a Solution We've used the equations...

Homework Statement If a train 110 m long passes a telegraph pole in 3 seconds, then the time taken by it to cross a railway platform 165 m long is : Homework Equations The Attempt at a Solution 110 meters/3 seconds = speed of train using this ratio ((110 m)/(3 seconds)) * (110m+165m)=7.5...

Homework Statement A train speeds past a pole in 15 seconds and a plate form 100 m long in 25 seconds. Its length is : Homework EquationsThe Attempt at a Solution x/15 = (x+100)/25 after solving this equation x= 150. but the ans is 180 m ? what should be the correct ans.

Have been curious about a thought experiment where, given enough experimental data to train, a sophisticated enough neural network / deep learning program could 'discover' most of classical and quantum physics. Any thoughts?

Homework Statement Homework EquationsThe Attempt at a Solution for this class, we were not taught with contact ratio equations, nor the pressure angle is given, so for this type of problems, do we just assume that minimum number of teeth on a pinion will be 12? 3 integer factors of 180 can...

Homework Statement Homework EquationsThe Attempt at a Solution if you do 38*25/pi , you would get 302.394 for the exact pitch circle diameter, similarly, exact d2 should be 907.183 mm, is it a typo? or did I miss something?

Homework Statement Homework EquationsThe Attempt at a Solution Let's say that the last carriage gets uncoupled at time t = 0s and at this time the train has moved a distance ##l_0##.The resistive force could be given as ## F_r = AM##, where A is the appropriate constant and M is the mass of...

I am not a very careful person and I am often overly ambitious. I often think of something that would be cool to have then try to design or build it without considering safety or my abilities. Do you guys know how I could train myself to not be overly ambitious and to be more careful?

Homework Statement A locomotive is dragging empty freight cars, while coal is being dropped into them. It’s falling down into those freight cars with an efficiency (μ). Overall mass of the whole empty train is M. a) Calculate v(t) (velocity with respect to time), assuming that the force of...

Hello my constituents! Was having a discussion with a coworker of mine and we reached an impasse. If a train is in motion at regular traveling speed, what would happen if a motorcycle were to exit the train while moving? This question presented itself to us in the form of a movie we were...

I go to work on the train and I get on at the back and get off at the front. I can choose when to walk through the train. If I walk when the train is accelerating forwards it is harder for me to get to the front and I do more work. If I make the trip when the train is stopped or at a constant...

This is a thought experiment so the mentioned values are only for example purpose. I was wondering about an electrical train. So here is the setup, we have rails and an electric train with an overhead wire. In one case the train gets its power from DC and in the other case the train is powered...

Homework Statement A train has a length of 118 m and starts from rest with a constant acceleration at time t = 0 s. At this instant, a car just reaches the end of the train. The car is moving with a constant velocity. At a time t = 14.0 s, the car just reaches the front of the train...

Homework Statement A person standing on a train platform notices that the first train car, which is approaching the station, had passed him in 4 seconds, and that the second train car passed him in 5 seconds. After this, the front of the train stopped at the distance of 75 meters from the...

Hi everyone I am currently working with diesel railcars. To power the electrical systems, we have engines connected to alternators, which then connect to static inverters. The auxiliary power system runs off the static inverters, initially at 415V AC but distributed throughout the railcars at...

Homework Statement 12.81[/B] A train traveling at 20m/s is brought to an emergency stop. During braking, the acceleration is a=-(7/4)+(t/16) m/s^2, where t is the time in seconds measured from when the brakes were applied. (a) Integrate the acceleration from t=0 to t=16s using Euler's method...

Homework Statement A train sits on top of a 1% grade. It accelerates uniformly until it reaches level track. What is the velocity the the train reaches on the incline, and how far does it travel before it comes to a stop? There is a 50 N braking force applied. Homework EquationsThe Attempt at...

This is problem 12.81 from Pytels Dynamics 2nd edition 1. Homework Statement A train traveling at 20m/s is brought to an emergency stop. During braking, the acceleration is a=-(7/4)+(t/16) m/s^2, where t is the time in seconds measured from when the brakes were applied. (a) Integrate the...

Even if you're not a New Yorker, you probably know about the A train. And if you're a New Yorker or have visited New York, you may also know about the B, C, D, E, F, G, J, L, M, N, Q, R, S, V, W and Z trains. But you never hear about the H train. Have you ever wondered where it goes...

My little home made air-core solenoid makes 1.5T, why is it that superconducting electromagnets often aren't stronger than one would expect. Take the japanese maglev train for example: http://www.supraconductivite.fr/en/index.php?p=applications-trains-maglev-more According to this article the...