Train Definition and 638 Threads

Homework Statement A horizontal plywood disk with mass 6.90 kg and diameter 1.14 m pivots on frictionless bearings about a vertical axis through its center. You attach a circular model-railroad track of negligible mass and average diameter 1.04 m to the disk. A 1.40 −kg , battery-driven model...

This is adorable*. Is it true? http://digg.com/video/german-electric-train-start-music *if an electric train inadvertently does this as it's powering up

Homework Statement To determine the speed of a train, a student of Physics determined the frequency of the whistle in the approach to its position of observation, and measured 220 Hz. He then determined the frequency of the whistle when the train moved away, and got 190 Hz. What is the speed of...

Hello, I am someone who has no experience in physics other than primary/high school and I have a quick simple question about something I can't wrap my mind around as a complete physics newbie. Please have understanding. The question: let's say a train is standing still at a point in space (so...

Homework Statement You are standing on a train station platform as a train goes by close to you. As the train approaches, you hear the whistle sound at a frequency of f1 = 92 Hz. As the train recedes, you hear the whistle sound at a frequency of f2 = 79 Hz. Take the speed of sound in air to be...

a train accelerates uniformly from rest to a speed v m/s with uniform acceleration a m/s^2 it then decelerates uniformly to rest with uniform retardation 3a m/s^2. the total distance traveled is s metres. if the average speed for the whole journey is square root (s/2) find the value of a. does...

I'm somewhat of a slow learner. I am fine if I can spend a lot of time with something, but I can never solve a problem quickly on the spot or remember things the first time they are told to me. Do you guys have any suggestions on how I can train myself to become a faster learner?

Homework Statement Will a maglev train beginning at rest slowly drift or accelerate due to the rotation of the earth? Homework EquationsThe Attempt at a Solution The Earth is a rotating reference frame, with points on the equator moving at approximately 1000 miles per hour. If the maglev is...

Homework Statement [/B] Superman must stop a 120-km/hr train in 150 m to keep it from hitting a stalled car on the tracks. If the trains mass is 3.6 x 10^5 kg, how much force must he exert? Vi = 33 m/s (120 km/h) Vf = 0 m/s Displacement (Xf - Xi) = 150 m M = 3.6 x 10^5 kg Homework Equations...

I was talking to my Physics teacher about this at lunch. If I was to have an rc Helicopter which i had hovering perfecting (if only i had the skill) on a train at rest. What would happen in terms of the position of the helicopter as the train accelerated? Would is stay at the same point in...

What would happen?

Homework Statement A train has got five train cars, each one with N seats. There are 150 passengers who randomly choose one of the cars. What is the probability that everyone will get a seat? I think that what is asking me is "what is the probability that each wagon is chosen by no more than...

Homework Statement A train engine of mass ##m## is chugging its way around a circular curve of radius ##R## at a constant speed ##v##. Draw a free body/force diagram for the train engine showing all of the forces acting on it. Evaluate the total vector force acting on the engine as a function...

Hey all, I was re-reading my quantum mechanics books and I noticed that different books have different scenarios for the Einstein Train thought experiment. And I was just wondering if I understood it correctly. Scenario 1: A person inside a moving train flashes a light beam that goes in both...

Homework Statement As show in the figure below, balloon A (containing gas of density ##ρ_A##) and balloon B (containing gas of density ##ρ_B##) are each suspended by string from the ceiling of a train at rest. Balloon C (containing gas of density ##ρ_C## is attached to the train floor by...

The total distance traveled by trains is 18 km & the time spent is 20 minutes. Find the average speed of the train in kilometers per hour. I' m stuck right in the beginning in converting 20 minutes to hours by dividing from 60 which I get this recurring decimal 0.33333

Homework Statement On a train, there is a passenger who has an aquarium, filled with water. The aquarium's size: 40cm x 25cm x 25cm, and is filled with water up to the height of 20cm (5 cm remaining) What is the maximal deceleration of the train, such as the entire volume of water will remain...

I am puzzled over einstein's thought experiment on simultaneity. In this experiment, a man is standing on a train platform. A woman is sitted in the middle of a moving train traveling towards the man. When the train is half past the man, lightning strikes at the same instant at both ends of...

Hi, I'm going to pose my questions with a number of assumptions, so please pick me up on any that are wrong. I want to know the design choices behind electric trains historically and current, this will mostly require some context of induction motors and inverters. I don't know exactly how EMUs...

There's a section in my astronomy book on relativity. The image shows a train traveling at a slow speed and a second image of the train approaching the speed of light. The text says the second train is length contracted, but only in the horizontal direction. In the vertical direction the train...

Say a person is on a train moving to the right. He then flashes a light upwards perpendicular to the motion of the train. Directly on top of the person there is a mirror. If the light travels in a straight line why does it hit the mirror and bounce back? Why does the light act in a similar way...

I saw in an other topic the following thought experiment: In the middle of a train there is a bom with two lightdetectors. At both ends of the train there are two switchable lightsources. The two lightdetectors measure the respective light from both sources. We switch on both switches...

What formulas do Diesel Electric Locomotive manufactures use when designing new Locomotives? Are there any good books on the subject? Locomotive meaning train engine. I want to understand freight engine designs not passenger. Thank you, Kevin

Homework Statement My professor said that we needed to acquire a program that can solve the equation: I have not had any success. Can anyone point me in the right direction? Homework Equations 73.09 < (N3N5)/(N2N4) < 73.11 The Attempt at a Solution

Edit: Sorry, the title should say LIGHT, not time! << Mentor Note -- Title updated >> Let's say you're on a train, in the back of a car. The train is stationary. You shine a laser to the front of the car, and you can measure the time it takes for the laser to reach the wall. Now, if the train...

Homework Statement A train is traveling east along a straight run of track at 72.0 km/hr. Inside, two siblings 1.9 m apart are playing catch directly across the aisle. The kid wearing a P.J.Harvey T-shirt throws the ball horizontally north. The ball crosses the train and is caught 0.75 s later...

1. Two long trains pass each other head on with a relative speed of 0.97c. Bob, the driver of the first train notices that it takes 5.8 secs to pass the entire second train. How long do people on the second train say it takes for Bob to go by their train? 2. t = t0/(1-v2/c2)1/23. I understand...

Someone once said, there are no stupid questions, just stupid people. All the questions I have read about sound coming from an approaching object only seem to deal with the frequency of sound, not its speed. So with that in mind, I have the following (hopefully non-stupid) question: A train is...

Youtube vid of an Einstein's Train example: From the perspective of the man on platform, the rear of the train seems to be approaching the front lightning's light at greater than c (train's speed + c). Is this correct? I thought there was a rule against that...

Homework Statement The train is traveling in a gallery at ##v=70 km/h##. Outside air is not moving and pressure is ##p_0=101325 Pa## and temperature ##T=283 K ##. The area of the face of the train is ##A=9 m^2##. Determine the minimum area of the section of the gallery such that the pressure...

Hi, I am a freshman in high school (going into sophomore next September) and am trying to prepare for the IPhO. I was recommended to use Resnick and Halliday to learn the physics, and am currently doing that. However, I am still unable to solve USAPhO problems in areas that I have covered in...

Homework Statement A relativistic train of proper length 237 m approaches a tunnel of the same proper length, at a relative speed of 0.951c. A paint bomb in the engine room is set to explode (and cover everyone with blue paint) when the front of the train passes the far end of the tunnel (event...

Hello there, can anyone tell me what is a permanent magnet motor drive train and what is the working principle of permanent magnet motor drive train ? i have searched google but i couldn't find anything useful

Homework Statement a)a stationary railroad whistle is sounded. An echo is heard 4.0 seconds later by a train's engineer. If the speed of sound is 343 m/s, how far away is the reflecting surface? b) If the temperature of the air increased, how would this change your answer? Homework Equations...

What are the difference between them? What is that one in the photo?

Homework Statement [/B] Two cities are connected by a straight underground tunnel, as shown in the diagram. A train starting from rest travels between the two cities powered only by the gravitational force of the Earth, F = - \frac{mgr}{R}. Find the time t_1 taken to travel between the two...

Homework Statement "Assume that a train is traveling at 65 cm/s, and the track has radius 20cm. What is the magnitude of the train's average acceleration as the train goes from the tree marked A to the next tree B, located exactly 1/4 of the way around the track from tree A? [Hint: This...

Let us first review Einstein’s train and platform thought experiment which consists of one observer midway inside a speeding train car and another observer standing on a platform as the train moves past. A flash of light is given off at the center of the train car just as the two observers pass...

Homework Statement In a thought experiment, a train is moving at a speed of 0.95c relative to the ground. A pendulum attached to the ceiling of the train is set into oscillation. An observer T on the train and an observer G on the ground measure the period of oscillation of the pendulum. State...

If we take a look at the experiment were two observers A (inside a train) and B on the platform observering the train as it pass by. Person A will stand in the exact middle of the train and send out a light wave. Person A will observe the light to hit the wall at the same time, while person two...

I'm clueless when it comes to physics, so forgive me if this sounds stupid. But fot years I've wondered something, and no one seems to have an answer for it. If you are standing inside a moving bus or train, and you jump on the spot (straight up,not in the direction that the vehicle is moving)...

Hi, thanks for taking a look! A toy train rolls around a horizontal 1.4-m-diameter track. The coefficient of rolling friction is 0.12. (a) What is the magnitude of the train's angular acceleration after it is released? (b) How long does it take the train to stop if it's released with an...

Homework Statement When a train running at a speed of 72 km/h approaches a crossing signal, a passenger in the train hears the siren at 720 Hz. What frequency does the passenger detect after the train passes the crossing signal? Take the speed of sound in air to be 340 m/s. Homework Equations...

Hi, I have a question about where's the most efficient place for a train engine - Let's say a train has to do a some route back and forth, the route has curves and positive and negative slopes. In real life - What's the best position for the enginge? My intuition says it will be most efficient...

Here is a thought experiment which is a modified version of a one I posted 4 years ago. A moving train, where there are two slits at an equal distance from a photon source along the direction of motion open for a short period of time to allow the entry of photons from the source. The source...

check out this clip. http://gfycat.com/PowerfulThornyCanine if the circle was tight enough, like a corkscrew, could the sideways pulling cause the train to roll in/derail?

This analysis uses an AND gate, the very embodiment of simultaneity, for clarity. A 1km long train travels through a 1km tunnel at a speed of 0.6c=180m/microsecond. At each end of the tunnel is a photo-electric beam sensor, which can be blocked by the train. They are connected to an AND gate...

Hello I hope you know the phenomenon called "Magnetic train". My teacher used it in classes to demontrate electromagnetic phenomena. So he told the advanced learners (however, here I am xD) to investigate it, especially the forces and how certain parameters affect the velocity. But I do not...

Homework Statement The driver of an express train traveling at 38 m/3 [E] sees a freight train 120 m ahead on the same line traveling at a constant velocity of 12 m/2 [E]. He immediately applies his brakes and just avoids a collision. Assume that the freight train maintains its constant...