Measuring a Rod in a Running Train: Why?

[vinayjain]

Can anyone tell me what will happen to a length og a rod if it is measured in a running train and why?

 

[phinds]

For all practical purposes, nothing will happen. Down around the 15th decimal place or so, WAY below our ability to measure it, the rod will be shorter than if the train were not moving. This is assuming that you are talking about a real train, on earth, not a thought experiment with the train moving at a relativistic speed.

 

[vinayjain]

yup...I am talking about a real train and thanx.....but can u please tell me if not a realistic train say if train is moving at the 70% speed of light then what will happen

 

[phinds]

Well, both the rod and your measuring stick will shrink a bit but you won't notice it since they BOTH shrink.

 

[pmacias]

Measuring the length of a rod in a running train can produce different results compared to measuring it on a stationary train. This is because the train is in motion, which can affect the measurement due to the relative motion between the rod and the observer.

The length of the rod will appear shorter when measured in a running train. This is due to the phenomenon of length contraction, which was first proposed by Albert Einstein in his theory of relativity. According to this theory, objects in motion appear to be shorter in the direction of their motion when measured by an observer at rest.

In the case of a running train, the rod is moving with the train, and therefore, its length will appear shorter to an observer outside the train. This is because the observer is measuring the length of the rod from a frame of reference that is stationary, while the rod is moving. As a result, the measurement will be affected by the relative motion between the two frames of reference.

Furthermore, the speed of the train can also affect the measurement. The faster the train is moving, the greater the length contraction effect will be. This is because the relative speed between the rod and the observer will be higher, resulting in a greater difference in the measured length.

In conclusion, measuring a rod in a running train can produce different results due to the phenomenon of length contraction. This is a fundamental concept in the theory of relativity and is essential to consider when making precise measurements in a moving frame of reference.