Length Contraction

Question

At what speed does a meter stick move if its length is observed to shrink to $0.5$ m?

What would we think for this question? It doesn't seem too hard but couldn't work it out. That's why I want to take your thinkings.

Answer 1

From wikipedia $$ L=\frac{L_{0}}{\gamma(v)}=L_{0}\sqrt{1-v^{2}/c^{2}} $$ where $L_0$ is the proper length (the length of the object in its rest frame), $L$ is the length observed by an observer in relative motion with respect to the object, $v$ is the relative velocity between the observer and the moving object, $c$ is the speed of light.

So $L_0=1\mathrm{m}$, $L=0.5\mathrm{m}$ gives $$ v = \frac{\sqrt{3} c}{2} $$