In the length contraction formula l = l₀√(1 - v²/c²), what does the symbol l represent?

l is the contracted length measured by an observer relative to whom the object is moving.

In the length contraction equation, what does l₀ represent?

l₀ is the proper length, which is the length measured in the rest frame of the object.

In the context of length contraction, what does c represent in the formula?

c is the speed of light in vacuum.

State the formula for length contraction in special relativity.

l = l₀√(1 - v²/c²), where l is the contracted length, l₀ is the proper length, v is the relative speed, and c is the speed of light.

In which direction does length contraction occur for a moving object?

Length contraction occurs only in the direction parallel to the motion of the object.

What happens to the dimensions of a moving object that are perpendicular to its direction of motion?

Dimensions perpendicular to the motion remain unchanged; they are not contracted.

AQA A-Level Physics 7408

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Turning Points in Physics

Length contraction

2 things to know
Paper 3, section B

Overview

Proper length, contraction along the direction of motion, and when the effect becomes significant.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Numbers

What do l₀ and c represent in the length contraction formula?

Numbers

How does contracted length relate to proper length, and when does the effect matter?

Questions from this subtopic

Each one with the model answer underneath.

1
In the length contraction formula l = l₀√(1 - v²/c²), what does the symbol l represent?
Model answer
l is the contracted length measured by an observer relative to whom the object is moving.
2
In the length contraction equation, what does l₀ represent?
Model answer
l₀ is the proper length, which is the length measured in the rest frame of the object.
3
In the context of length contraction, what does c represent in the formula?
Model answer
c is the speed of light in vacuum.
4
State the formula for length contraction in special relativity.
Model answer
l = l₀√(1 - v²/c²), where l is the contracted length, l₀ is the proper length, v is the relative speed, and c is the speed of light.
5
In which direction does length contraction occur for a moving object?
Model answer
Length contraction occurs only in the direction parallel to the motion of the object.
6
What happens to the dimensions of a moving object that are perpendicular to its direction of motion?
Model answer
Dimensions perpendicular to the motion remain unchanged; they are not contracted.

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