Special relativity, simultaneity

In summary, the speed of the train and the distance between the strikes were given to determine the time separation according to an observer on the train. Using Lorentz transformations, the result is that the observer on the train sees the front strike first, then the back strike, with a time separation of approximately 2.4691358 x 10^-13 seconds. This may seem small, but the train's speed is much slower compared to the speed of light. The order of the strikes is logical and the answer is confirmed by another person.
  • #1
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Homework Statement


A train of 0.8 km (measured by an observer over the train) travels at a speed of 100 km/h. Two lightnings strike simultaneously the back and the front of the train, according to an observer on the ground. What is the time separating both strikes according to the observer on the train?

Homework Equations


Lorentz transformations.

The Attempt at a Solution


Let O be the reference frame of the observer on the ground and O' be the frame of reference of the observer on the train.
They give me the information [tex]x_B'-x_A'=800m[/tex] and [tex]t_B-t_A=0[/tex]. They ask me [tex]t_B'-t_A'[/tex].
Using Lorentz transformations, I get that [tex]t_B'+\frac{vx_B'}{c^2}-t_A'-\frac{vx_A'}{c^2}=0[/tex].
I converted the km/h to m/s and my result is that [tex]t_B'-t_A'=-2.4691358 \times 10 ^{-13}s[/tex]. It means therefore that [tex]t_A'>t_B'[/tex], thus the observer on the train sees first the strike of the lightning on the front of the train and then the one on the back of the train and their time separation is about [tex]2.4691358 \times 10 ^{-13}s[/tex].
I don't know if it's true. To me it seems a too little time, although I realize that the train is only moving at [tex]\frac{1000m}{36s}\approx \frac{30m}{s}[/tex] which is very small compared to c. The order of the strikes seems logical to me...
Can someone confirm/infirm my result?
 
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  • #2
Your answer is correct.
 
  • #3
Doc Al said:
Your answer is correct.

Ok thank you, good to know. Problem solved.
 

Related to Special relativity, simultaneity

What is special relativity?

Special relativity is a theory developed by Albert Einstein in 1905 that describes how objects move at speeds close to the speed of light. It explains how time and space are affected by an object's velocity, and it is the foundation of modern physics.

How does special relativity affect simultaneity?

Special relativity states that simultaneity, or events happening at the same time, is relative to an observer's frame of reference. This means that two events that appear simultaneous to one observer may not appear simultaneous to another observer in a different frame of reference.

What is the concept of time dilation in special relativity?

Time dilation is the idea that time moves slower for objects moving at high speeds. This is a consequence of special relativity and is caused by the stretching of space and time due to an object's velocity. This effect has been proven through experiments and is an essential part of modern physics.

How does special relativity impact our understanding of space and time?

Special relativity revolutionized our understanding of space and time by showing that they are not absolute but are instead relative to an observer's frame of reference. It also introduced the concept of four-dimensional spacetime, where time is considered the fourth dimension.

Can special relativity be applied to everyday situations?

Yes, special relativity has practical applications in many areas, including GPS technology, particle accelerators, and space travel. It also helps us understand phenomena such as cosmic rays, black holes, and the behavior of subatomic particles.

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