Proper length is the length of an object as measured by an observer at rest relative to that object.
To measure proper length, both measurement events must be done simultaneously.
Fun fact: Proper length is also the longest length you can determine for an object!
How is proper length affected by motion?
Objects appear to contract in length when observed from a frame that is moving relative to the object. This is known as length contraction.
Real-world example: Think of a train passing by you at super high speeds. If you could observe it under the laws of relativity, it would look shorter than if it was stationary!
Mathematics of proper length
In a stationary frame S: L0 = x2 – x1
In a moving frame S′: Length changes to L′ = \(\frac {L_o}{y}\)where γ is the Lorentz factor (more on that soon!).
Important formula: L0 = γL′
Deep dive - lorentz factor 🧠
It's represented by γ and can be calculated using: γ = √1−c2v21
Basically, it helps us understand how much an object contracts or time dilates due to relativistic speeds.
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Physics HL
Theme A - Space, Time & Motion
Unlocking Proper Length & Relativity: Deep Dive Into Lorentz Transformations
Proper length is the length of an object as measured by an observer at rest relative to that object.
To measure proper length, both measurement events must be done simultaneously.
Fun fact: Proper length is also the longest length you can determine for an object!
How is proper length affected by motion?
Objects appear to contract in length when observed from a frame that is moving relative to the object. This is known as length contraction.
Real-world example: Think of a train passing by you at super high speeds. If you could observe it under the laws of relativity, it would look shorter than if it was stationary!
Mathematics of proper length
In a stationary frame S: L0 = x2 – x1
In a moving frame S′: Length changes to L′ = \(\frac {L_o}{y}\)where γ is the Lorentz factor (more on that soon!).
Important formula: L0 = γL′
Deep dive - lorentz factor 🧠
It's represented by γ and can be calculated using: γ = √1−c2v21
Basically, it helps us understand how much an object contracts or time dilates due to relativistic speeds.
Unlock the Full Content!
Dive deeper and gain exclusive access to premium files of Physics HL. Subscribe now and get closer to that 45 🌟