Train Definition and 650 Threads

Homework Statement The engineer of a passenger train traveling at 25.0 m/s sights a freight train whose caboose is 200 m ahead on the same track. The freight train is traveling at 15.0 m/s in the same direction as the passenger train. The engineer of the passenger train immediately applies...

A train (source) approaching a stationery observer, wavelength of the sound is equal to the distance between source and observer, How?

Homework Statement The engineer of a passenger train traveling at 25.0 m/s sights a freight train whose caboose is 200 m ahead on the same track. The freight train is traveling at 15.0 m/s in the same direction as the passenger train. The engineer of the passenger train immediately applies...

The problem statement A train starts out from Stavanger at 8.14, in direction of Kristiansand. It goes with constant speed, 80.0km/h until Sandnes, a distance of 15.0 km. Then it accelerates (instantaneously) to 120 km/h and proceeds towards Kristiansand. Kristiansand is 250 km from...

I'm seeing examples where for the person in the train the offset of both lights at the end of the train are not seen as simultaneous, while for the observer on the platform it is seen as simultaneous - and vice versa from other sources. What's going on? Furthermore, if my school textbook is...

Hi guys, I've been thinking about this experiment for the last few hours and I have a few questions which I am deeply confused about. 1) In the light clock experiment, where light clock is set up so that light travels vertically, and the train carrying the clock travels horizontally, wouldn't...

When I look at the top of the gif, the train comes toward me. When I look at the bottom, it goes away from me. I have a hard time making it change while looking at the same spot, though.

This is not a problem, it is just a concept check :shy: What does it mean that something does not impart linear momentum to the rest of the system? For example grain leaking out a train car.

Homework Statement Two trains, one traveling 60.0mph east and the other traveling 90.0mph west, are on the same track. When they are 10000 ft apart both train's brakes are applied. If they both have the same deceleration, what is the minimum deceleration to prevent a collision? Homework...

There is a homopolar generator on a train moving at 215 km/h. The magnet of the generator is attached to the disk so they would rotate together, but they are stationary now, except that they are moving along with the train. Is there any current generated by the generator? I expect the answer...

Hi, we've recently been set a task by our physics teacher to try and calculate the Young's Modulus of Spiderman's webs in the train stopping scene of Spiderman 2. Doing research on the mass of the carriage + passengers, calculating forces from that and also using things like the velocity...

Hello. I've searched a lot on the internett on jumping inside a train, and I do only find solutions for the question "When u jump inside a train will u land at the same spot, whereas the train is moving u should land bit back". What happens if you are running and jumping backwards, would you...

Homework Statement A train passes through an electric post in 10 seconds. With same velocity, it passes through a 2km long bridge in 110 seconds.Find the velocity of the train: a)18kmph b)36kmph c)72kmph d)90kmph. Homework Equations The Attempt at a Solution...

Homework Statement Train is moving along the x-axis with speed v relative to platform, inside the train mosquito is flying with 3D speed v0. 1) Write mosquito s 4-speed components with respect to train coordinate system. 2) Using 4-vector component transformation write mosquito's 4-speed...

Lets have a train moving to the right side in the shown direction of the arrow. From a point near the end A, 2 rays of light are emitted toward both ends A and B so as they appear to reach both ends at the same time for an external observer. At the moment the 2 rays reaches the 2 ends at the...

Homework Statement A train wheel's have a coefficient of 0.08. What is the steepest slope the train can climb? Homework Equations Friction force = coefficient x component of train's weight perpendicular to slope x 9.81 If the train is on the point of slipping Friction force =...

1. If a train engine is traveling with initial velocity 'u' and the guard's coach(last coach of the train) is found to cross a pole with velocity 'v', then what is the velocity of the midpoint of the train at that instant?

Time Question -- how long did the train block the crossing? Homework Statement A commuter train 500 m long travels on a straight track at a speed of 78.6 km/h it slows down as it approaches a crossing. The last car passes the crossing at a speed of 15.8 km/h. With a constant acceleration, how...

Homework Statement Two trains A and B are moving with speed 20m/s and 30m/s respectively in the same direction on the same straight track with B ahead of A. The engines are at the front ends. The engine of trains A blows a long whistle. Assume that the speed of sound of whistle is...

Homework Statement See attachment. Homework Equations The Attempt at a Solution Equations (1) and (2) describe this gear train system. I'm confused about them. For (1): If I rewrite it (∑F=0 format) I get: T-T1-Jθ''-Bθ' = 0 The figure clearly shows θ1 positive spinning...

I recently watched a video in Einstein's train though experiment. www.youtube.com/watch?v=wteiuxyqtoM From what I got from it, events can appear to be at different times when compared to each other depending on the observer. But isn't there an absolute event timing of when the events...

Homework Statement Two train whistles have an identical frequency of 246 Hz. Train A is motionless in the station and sounds its whistle. Meanwhile, Train B is pulling into the station and sounds its whistle. The conductor of Train B hears 5.39 beats every second. How fast is Train B moving...

Consider the thought experiment in the diagram below. According to the authors, the vector will rotate even in the rest frame of the moving train relative to the body of the train. Is it possible to consider the spin axis of the gyroscope represented by the vector as a simple rod and...

Homework Statement You are an engineer working for a new interstate bullet train start-up company. Your manager, Saul Enderman, is charged with designing the first 1500-meter-long segment of a new train line. (Another team is in charge of designing the remaining segments of the line.) During...

This was from my last exam. I got this problem wrong. I feel like I should have known how to do it but I blanked out or something. Just coming here to figure out how it's supposed to be done. (This is from what I remember, numbers may be off from what was on the test) I know I got it wrong...

Here is another train and platform example, offered to examine ghwellsjr's view equating what you see with what is real. Assumptions: Train has proper length 100. Platform has proper length 60. Train and platform are in relative inertial motion at 0.8c. There are two observers on the...

Hi all. I'm a run-of-the-mill layman—not a student. I've just developed an interest in physics lately and have been watching/reading a lot pop physics. So hopefully my question's not too stupid and hopefully the answer's not too far over my head. My question is about the thought experiment...

Homework Statement A high-speed train is traveling from Capital City to Shelbyville. According to an observer at rest on the ground, the clocks at the railroad stations in Capital City and Shelbyville both strike noon at the same time. According to a passenger on the train, when the Capital...

Homework Statement A train with proper length L moves at speed 5c/13 with respect to the ground. A ball is thrown from the back of the train to the front. The speed of the ball with respect to the train is c/3. As viewed by someone on the ground, how much time does the ball spend in the air...

Homework Statement Here the gear B is fixed and C and D are on the same drive. If C has 100 teeth, B has 50, D has 50 and E has 200. Calculate the ratio of the gearbox. Homework Equations The Attempt at a Solution My attempt is uploaded as an attachment as putting tables in...

I recently came across this paper http://arxiv.org/abs/physics/0504110v2 by Oas that is a semi-rant about how pedagogically evil relativistic mass is. He gives the following sample question: From the context, it appears that the students are expected to have little or no background in...

Hi all, I'm sure that things similar to this have been covered before. Also, I'm sure that a Minkowski diagram would probably clear things up no end but, anyway, please bear with me. Let's assume that we have our familiar railway carriage packed with observers who are satisfied that they...

Homework Statement A cart, starting at rest, is below a hopper at t=0. The hopper drops coal into the cart at a constant rate μ. At t=0 a constant force starts pushing the cart to the right and the coal begins to fall. The force ends once the back of the cart passes the hopper. A) Find...

i need to know how to calculate the inductance and field strength of a coil while another coil directly beneath it is turning off and coils under that are also turning off i also need to know how quickly the coils will turn off and if i can accelerate the process if it makes a difference the...

Homework Statement Two trains start from rest from two stations 5.0 km apart and travel, on two parallel railroad tracks, in opposite directions. One train accelerates uniformly at 2.5 m/s^2 and the other has a constant acceleration of 4.0 m/s^2. How far from the first station will they...

Please help with this. This is similar to the Einstein train experiment. When C and C' are at the same place, lightning strikes at their location. Both survive though. Assume another prime B' behind C' When B' is at the same location as C, the lightning is at (A,0,0) and (-A,0,0) in the C...

https://scontent-a-ams.xx.fbcdn.net/hphotos-prn1/601539_10201811069735094_388925769_n.jpg Why did they define the lightning event to be simultaneous for Stanley? Why can't it be simultaneous for Mavis, so that the lighting hits A first?

Homework Statement Two trains are traveling toward each other at 30.0 m/s relative to the ground. One train is blowing a whistle at 480 Hz. (a)What frequency is heard on the other train if the wind is blowing at 30.0 m/s toward the whistle and away from the listener? (assume the speed of sound...

Homework Statement A car and a train collides with each other in an elastic collision. The mass of the train is much more larger than the mass of the car. Ignore air resistance and friction from the railway tracks and roads. Just before impact the car has a velocity of (V) train has a velocity...

Homework Statement A 60,000 kg train is being pulled up a 1% gradient by an engine exerting 3 kN. The frictional force opposing the motion of the train is 4 kN. The train’s initial speed is 12 m/s. Through what horizontal distance will the train move before it’s speed is reduced to 9 m/s...

Homework Statement This is a final hurdle of a long question designing a simple gear train. That is done but now am not sure of my calculations for power in / out and torque in and out, so hopefully someone can help? OK - I have 4 spur gears inline, Gear A = 100 rpm 80 Teeth (input motor...

Hi , I observed an older type of electric train yesterday which is a DC train having a +ve overhead wire with around 3000v in it. Now as I was sitting there I saw the capacitor banks below the train , probably used to smooth the incoming voltage for peaks and stuff to feed that further to the...

Homework Statement A bored but observant child on a moving train ties a ball to one end of a string and ties the other end to a light fixture on the ceiling of the train. When the train slows down, the child notices that the string is no longer hanging straight down but instead makes an angle...

So I asked this question in another thread but thought the question was probably best asked here in this forum to at least understand part of the experiment. My idea follows the traditional train and platform analogy that is used in many thought experiments to explain the issue of simultaneity...

Homework Statement An empty freight car of mass M starts moving from rest with a constant applied force F0. At the same time, coal runs into the car at steady rate b from a hopper above the car at rest along the track. Calculate the velocity of the car as a function of time. Data: M = 1900...

Homework Statement A train moves at speed v. Bullets are successively fired at speed u (relative to the train) from the back of the train to the front. A new bullet is fired at the instant (as measured in the train frame) the previous bullet hits the front. In the frame of the ground, what...

Homework Statement Two trains, A and B, are moving towards each other with relative speed 0.8c. The passing of the two trains (from when their fronts align to when their backs align) takes 20% longer as observed from train A as is does as observed from train B. What is the ratio of the length...

Square Pulse Train Fourier Series help?? Homework Statement problem+directions below: Homework Equations ω=2\pif β=\frac{2\pi}{\lambda} The Attempt at a Solution Since the problem asks to make all time-dependent sinusoidal functions deal with x-direction, i don't think i need to...

Homework Statement A train is traveling down a straight track at 20 m/s when the engineer applies the brakes, resulting in an acceleration of -1.0 m/s2 as long as the train is in motion. How far does the train move in a 40-s time interval starting at the instant the brakes are applied...

Imagine a set of train tracks. Now there is one bridge (a resistor) connecting the two rails in one spot. On a different spot, there is rolling axle that acts as another bridge and it makes good electrical connection with the rails creating a full rectangular circuit. This axle rolls at a...