How Do Clocks on Moving Trains Behave Near a Tree?

In summary, the conversation discusses the problem of finding the reading on the clocks at the backs of two trains passing each other at a tree, while taking into account special relativity. The problem involves three different scenarios: a) standing next to the tree on the ground, b) being on one of the trains, and c) being one of the trains observing the other train's clock. The relevant concepts for this problem include time dilation, length contraction, and relativity of simultaneity. It is suggested to first revise and understand these concepts before attempting the problem.
  • #1
Dennydont
45
0

Homework Statement


Two trains of proper length L move toward each other in opposite directions on parallel tracks. They both move at speed v with respect to the ground. Both trains have clocks at the front and back, and these clocks are synchronized as usual in the frame of the train they are in. A tree is located on the ground at the place where the fronts of the trains both read zero when they pass. Find the reading on the clocks at the backs of the train when they (the backs) pass each other at the tree. Do this in three different ways:
a) Standing next to the tree on the ground, and you observe what one of the rear clocks is doing.
b) Imagine that you are on one of the trains, observing what your own rear clock is doing during the time the tree travels relevant distance.
c)Imagine that you are one of the trains, observing what the other train's rear clock is doing during the time the tree travels the relevant distance.

Homework Equations


I'm not even sure what equations are even relevant for this problem.

The Attempt at a Solution


I am so lost and don't even know where to begin with this problem. Special relativity just isn't my thing. Can someone please at least help in pointing me in the right direction?
 
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  • #2
I'm not quite sure about c but I believe a and b are simple. If it is asking what I think it is asking, use the time dilation equation for using the proper time interval to find the dilated time interval. Just remember that the tree clock has the proper time interval. Then, if you need to explain it in words, remember that a larger time interval means there is more time between ticks on a clock.
 
  • #3
Dennydont said:

Homework Statement


Two trains of proper length L move toward each other in opposite directions on parallel tracks. They both move at speed v with respect to the ground. Both trains have clocks at the front and back, and these clocks are synchronized as usual in the frame of the train they are in. A tree is located on the ground at the place where the fronts of the trains both read zero when they pass. Find the reading on the clocks at the backs of the train when they (the backs) pass each other at the tree. Do this in three different ways:
a) Standing next to the tree on the ground, and you observe what one of the rear clocks is doing.
b) Imagine that you are on one of the trains, observing what your own rear clock is doing during the time the tree travels relevant distance.
c)Imagine that you are one of the trains, observing what the other train's rear clock is doing during the time the tree travels the relevant distance.

Homework Equations


I'm not even sure what equations are even relevant for this problem.

The Attempt at a Solution


I am so lost and don't even know where to begin with this problem. Special relativity just isn't my thing. Can someone please at least help in pointing me in the right direction?

It's difficult for us to help you with your homework if you are so lost with the material. My suggestion is you have to go back to the material and try again to understand it. This question is not the easiest, so I also suggest you look for some easier questions to get you going then come back to this one.

Try revising:

Time dilation
Length contraction
Relativity of simultaneity ("Leading clocks lag")

And try some questions for each of these topics first.
 

1. How do you solve the "Two trains and a tree" problem?

The "Two trains and a tree" problem can be solved using the distance formula and setting up equations to find the time when the two trains meet at the tree.

2. What is the purpose of the "Two trains and a tree" problem?

The "Two trains and a tree" problem is often used as an example in mathematics and physics to demonstrate the concept of relative motion and how it can be applied to real-world situations.

3. Are there any assumptions made in the "Two trains and a tree" problem?

Yes, the problem assumes that the trains are moving at a constant speed and in a straight line, and that there are no other factors affecting their motion such as wind or changes in the track.

4. Can the "Two trains and a tree" problem be solved using different methods?

Yes, there are multiple approaches to solving the "Two trains and a tree" problem, such as using algebraic equations or graphing the distances and finding the intersection point.

5. Can the "Two trains and a tree" problem be applied to other scenarios?

Yes, the concept of relative motion and the equations used to solve the "Two trains and a tree" problem can be applied to various situations, such as two cars driving towards each other or a boat crossing a river.

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