A spaceship travels with a speed of 0.3c as it

passes by the Earth on its way to a distant
star, as shown in the diagram below. The
pilot of the spaceship measures the length of
the moving ship as 40 m.
0.3 c
Earth
Determine its length as measured by a person on Earth.
Answer in units of m

1 answer

β= v/c=0.3c/c=0.3
L=L₀•sqrt{1-β²)=30•sqrt(1-0.3²)=28.6 m