Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Possible Duplicate:
Help Me Gain an Intuitive Understanding of Lorentz Contraction

Frames k and k' are inertial frames. Frame k' is moving at a velocity of magnitude v relative to frame k in the direction of the x-axis. there are rigid rods in each frame oriented along the direction of the relative velocity. Someone in frame k measures the rod that is stationary in k as having length L1 and the rod stationary in frame k' having a length L'2. What are the lengths of the rods measured by someone in frame k'?

share|cite|improve this question

marked as duplicate by Qmechanic, Manishearth, Waffle's Crazy Peanut, Sklivvz Dec 29 '12 at 15:18

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

This looks like a homework assignment... – Sklivvz Dec 29 '12 at 13:52

The answer is length contraction, the lengths of the first is $L1\sqrt{1-v^2}$, it gets contracted, while the length of the moving one is $L2/\sqrt{1-v^2}$, so that after contraction it gives the right answer. The details of the geometry is explained in my answer here: What are the mechanics by which Time Dilation and Length Contraction occur? .

share|cite|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.