Length contraction

Definition

Length contraction is the phenomenon where the length of an object moving at relativistic speeds appears shorter along the direction of motion when observed from a stationary frame of reference. This effect is a direct consequence of Einstein's theory of special relativity.

5 Must Know Facts For Your Next Test

1. Length contraction only occurs in the direction parallel to the object's motion.
2. The formula for length contraction is $L = L_0 \sqrt{1 - \frac{v^2}{c^2}}$, where $L$ is the contracted length, $L_0$ is the proper length, $v$ is the velocity of the object, and $c$ is the speed of light.
3. At speeds much less than the speed of light, length contraction effects are negligible.
4. Length contraction becomes significant as an object's speed approaches the speed of light.
5. Observers moving with the object do not perceive any length contraction; it only occurs relative to stationary observers.

Review Questions

• What happens to an object's length as its speed approaches the speed of light?
• Write down and explain the formula for length contraction.
• Why do observers moving with an object not notice any length contraction?

Related terms

Special Relativity: A theory in physics proposed by Albert Einstein that describes how time and space are linked for objects moving at constant speeds close to that of light.

Time Dilation: A phenomenon predicted by special relativity where time passes slower for an observer in motion relative to a stationary observer.

Lorentz Transformation: Mathematical equations that describe how measurements of space and time by two observers are related in special relativity.