Answer to Question #336083 in Physics for Student 11

Question

A meter stick which is 100 cm is moving with an observed length of 60 cm. What is its speed?

Answer 1

$$l=l_0\sqrt{1-v^2/c^2}$$

$$v=c\sqrt{1-(l/l_0)^2}\\ =c\sqrt{1-(60/100)^2}=0.8c$$