Train Definition and 638 Threads

Hi, so I first converted the speeds to meters per second (m/s), and then proceed to finding if they will clash using 2ad = v^2 - v0^2 assuming v0^2 is zero to find their final position. Red train speed: 20 m/s Green train speed: 40 m/s The stopping distance d for red train is 200 m and the...

I tried to come up with answers using the spacetime interval equation. (Δs)^2 = (c*Δt)^2 - (Δx)^2 Let train's frame of reference be S. Δt = 0 Δx = 500 m (since proper length is measured in object's rest frame) Then I get (Δs)^2 = -250,000 Since L = L0 / lorentz factor, where L0 is the proper...

Assume it’s extremely bright and sunny outside the tunnel, but very very dark inside the tunnel If you are a passenger riding in the “center” of the train , and the shutting and opening of each door (the tunnel entrance and tunnel exit door) happens very fast and occurs at a point where one...

The problem and solution are, However, I don't understand why the answer is correct. I think that time should be dilated since ##\Delta t = γ \Delta t_0 = 2γ## where ##γ \geq 1## for ##v \geq 0##. Does anybody please know what I'm doing wrong here? Thanks!

Hello! I can do this task just using this formula s=u*t+a*t^2/2. But just saw an example where someone used this Galileo toerem. Here is task: "An observer stands on the platform at the front edge of the first bogie of a stationary train. The train starts moving with uniform acceleration and...

Hello Let's suppose we have 2 observers. One is in Einstein's train and one is outside. There are 2 mirrors: one inside the train and one outside. Speed of train is v Both observers emit light which reflects from both mirrors. What will be the speed of reflected light for both observers from...

I am trying to train a model to generate images, I have a dataset of over 17K of men posing. I have been training my model for a few hours now and Sadly all I am getting is this: Also my d_loss=-9.79e+3 how is it Negative ? here is my code: # -*- coding: utf-8 -*- """BigGANModel.ipynb...

I think, since the train is decelerate the kid will fall off at free falling. the time for that is: y=0.5*9.8*t2 ⇒ t=√(2*y/g)=√(2*3/9.8)=0.8sec. Now i think i need to find what is the distance the train is doing in this time, but i can't figure this out.

For part (b), The solution is, However, if the acceleration was not constant during the 21 ms, then would the power required be larger? I believe the average power required would be larger because if the train started off at a lower speed and then speed up very rapidly towards the end...

For part (c) of this problem, The solution is, However, how did they know that the fictitious force that acts on the mass until the string become taut (T = Ma from as observed by an observer at rest outside) has a magnitude of Ma (assuming that the observer has no communication with the...

I have not seen this exact configuration discussed. Observer A in middle of train. Observer B at station. Both A and B think the other is moving. Observer A synchronizes two clocks and puts one at each end of train. Lightning strikes both clocks stopping them when A passes B. B says...

I was doing one of MIT's 8.01.1x course and came across this question. In case 2, how would we be able to theoretically calculate the horizontal acceleration in this non-inertial frame? The course said that Newton's Law do not hold in accelerating frames. However, could we find the...

My choice is C, which is "equal to." Here is my reasoning: The engine pulls on car 1, so car 1 is having a force acting on it, which pulls car 1 forward. Likewise, the same amount of force is applied on car 2 by car 1 by moving forward with the same amount of force from the beginning. So it is...

How do you calculate the terminal velocity of the train moving in a coiled copper wire with two magnets attached to the polar ends? I have attached someone else's work I've found on the internet here and need help

1) really does not make sense to me. It is not clear to me how light could be reflected in multiple directions if the source is not a tilted mirror or another object with specific properties. I think the thought of the "point" P confuses me. Further, the fact that light travels in the opposite...

In the two hours the wave is traveling from event 1600km offshore to land would eight waves/crests be produced: 2hours/T=15minutes be correct ? Eight cycles = eight waves in the train. * I asked on another physics forum. No reply. "Tried" to register on several oceanography forums.

I kind of just made up the questions. I realize this is a basic question but my knowledge of physics is very limited.q1 answer v_left_ball = v_left_ball - v_train v_right_ball = v_right_ball + v_train q2 answer To get the speed from Bob's frame I would use v_Bob = v_Bob + v_Alice To get the...

I was wondering, if the magnet train is propelled by putting same polar magnet face each other at an angle and its natural magnetic property same pole repel, that's how it'spushing the train faster and faster...now what if we create a circular tunnel and have the train push itself and repel...

Summary:: Ecommerce in Long express train journey. Your views and opinion regarding this potential facility provided on one of the Long express train journey.

I'm speechless. Presumably other PF members won't be. :wink: https://arstechnica.com/science/2022/01/goldfish-can-learn-to-drive-and-navigate-terrestrial-environments/

The question is below; My approach; and kindly note that i am comfortable in using the si units. Here i used, ##60##km/hr = ##16.66666##m/s. For part (a), using the ##v-t## graph, ##→s_1##=(##\frac {1}{2}##×##180×16.666)##+(##\frac {1}{2}##×##60##×##16.666##) ##=1500+500=2000##m...

Find the questions and its solution below; Now would i be correct to use; ##v= u +at## where i considered ##v=33.3##m/s and ##u=16.67##m/s as the given average velocities between the two points in reference. Then it follows that, ##33.33=16.67 + 150a## ##→a= 0.11## We are told that ##a## is...

A, the train speed up?

(a) $$P(X≥10)=∫_{10}^∞10e^{−10x}dx=e^{−100}$$ (b) $$E(X)=∫_0^∞10xe^{−10x}dx=\frac{1}{10}$$ (c)$$\frac{10e^{−10}}{P(X≥10)}=10e^{100−10x}=\text{the new probability distribution for}\quad x≥10$$ $$E(X)=∫_{10}^∞10xe^{100−10x}dx=\frac{101}{10}$$😒 (d) imho it's unclear which "probability...

Do smartphone users get good cellular service as well as good cellular data while on a moving passenger train? This is assuming no wi-fi available.

I tried to graph this equation, but all I am getting is a straight line that is x=0. I don't understand what I am doing wrong.

i am having some hard time thinking about this problem: It is basically this: Imagine a bulb and a receptor distant L from each other (at the same axis x) inside a room, the roof of the room is at a height d from the bulb and receptor. Now you are at a train moving horizontally, parallel to...

I'm not sure if my answer is correct but I think the answer is false. Thank you for your help :) -sun1108

Assuming I'm in a train moving at a very high speed. According to Newton if I jump up, I must land at the same place. But what if I had the aptitude/ability to jump very very high, will I be moving in the air and land at the same place.

Hi, I was reading this article, https://science.howstuffworks.com/question456.htm, about firing a bullet from the back of train which is moving as fast as the bullet. The following is taken from the article mentioned above. So, ideally, the bullet will fall straight to the ground as it exits...

I have several confusion about this question: 1) Since the sand spilling out downwards, it means that there is change in momentum in vertical direction (before the sand spills and after the sand spills) but no change in momentum in horizontal direction so no net force in horizontal direction...

I know that the magnitude of the eddy currents is proportional to the magnetic field, which means it should increase as I add more magnets. However I am unsure if this approach is correct.

Hi everyone, I'm an Italian High Schooler and I need a problem about maglev trains for the final exam. I apologize in advance if my english is bad or if I didn't follow some rules. I'm not native and new to this forum.

How did you find PF?: Online [Thread moved from the New Member Intro forum, so no Schoolwork Template is shown] Hi. I'm new and am trying to solve a simple question 'Find the max power of a train engine traveling level at 50 metres per second if total resistance to motion is 30 KiloNewtons...

I want to solve this question first using the train frame, and so going to the ground frame, but the things got wrong, so i would aprpeciate to know why. I mean, there is another ways to solve it, but i want to know where is the error here. Simply, in train frame the time elapsed between the...

Hello, I'm after some advice/ clarification on some gear train design. This may just be a simple clarification Requirements I have a lead screw which needs to be supplied power by a Motor. This Lead screw must have 140Nm Torque to raise and lower the load, and must turn at 200RPM. The motors I...

So I am currently trying to model a MAGLEV train using COMSOL (high school research project). My project uses AC and DC motors as alternatives to the current maglev infrastructure and transportation. I first created a prototype through CAD Onshape, then created it in real life and applied my DC...

(a) No, a person seated inside the train compartment will not be able to tell whether the train is accelerating on a horizontal track or moving uniformly up an inclined track by observing the plumb line. (b) I am assuming that both observers are not allowed to look "out" of the boundaries of...

"(a) How much time does this take in the ground frame? (b) What is the person’s speed with respect to the ground? (c) How much time elapses on the person’s watch?" I solved it, but i am with a doubt yet wrt to the letter b. We can find that the train length in the ground frame is 4L/5, so, why...

We can find the difference of time to light reach both clocks, it should be Lv/c², what i am confused is why the rear clock show a higher reading of the front clock. Ok, the light take longer time to travel and reach the rear clock, and here is the thing! What i am interpreting is: When the...

a) So I think I solved a. "The length of B is such that A says that the fronts of the trains coincide with at exactly the same time as backs coincide." This tells us that in A's frame, B has the same length as A. So ##L_{observed}## in A's frame is simply ##L##. To obtain the proper length of B...

I've gone back to review special relativity in preparation for GR. I apologize for the horrific handwriting. a) So the ground frame measures the length of the train to be contracted by ##\frac{4}{5}##. So ##L_G = \frac{4L}{5}##. To calculate the total distance the train travels in the ground...

https://www.physicsforums.com/attachments/269029 Lightning strikes A and B simultaneously in the Embankment frame. M' sees the flash at B before the one at A. But if the flashes are simultaneous in the Train frame, does M' still see B before A?

Hi, In theory its a simple question. What am I missing?

I am confused about how to find the length of a wave train emitted within a time interval T and that is moving with speed c relative to a moving frame that is itself moving with velocity v. Apparently the answer is that the wave train's length is cT - vT, but I tried to plug in variables into...

So my work includes using the acceleration formula a=delta v/t (Vrtf-Vrti)/a -> (0-54)/(-0.31) -> t=174 seconds I plug in 174 seconds to find the acceleration of the left train. and got -0.22m/s^2 I then used the displacement equation x=(1/2)at^2+Vo+So coming out with Xrt=4703m and Xlt=...

Summary:: How can I measure the friction of a train with its rails and the air. How can I measure the friction of a train with its rails and the air. You can assume that the face of the train is like the picture below. If you need any specifications just let me know

Is there some rule of a thumb formula, which would be able to calculate the energy consumption of a train, based on the following parameters: - mass of the train - its speed - inclination It can be a simple approximation. I would be grateful for any kind of reply.

I have a "262 Lionel Line" O gauge train, from the early 1930's. It has sentimental value, my Father-In-Law (RIP) got it as a gift when he was about age 10. I've set it up each Christmas, a short track around the tree. But it is difficult to control, the gearing is high (it goes fast), so...