Question

according to Bob, on earth, it is 20 ly to planet y. anna has just passed earth, moving at constant speed v in a spaceship. when anna passes planet y, she is 20 years older than when she passed earth. calculate v

Answer 1

300000 KM/Sec

Step-by-step explanation:

Distance between the Earth and Planet Y = 20 LY

One light year is the distance traveled when traveling at the speed of light which 300000 KM/Sec.

Anna passed the Earth traveling at speed v. After reaching planet Y, she is 20 years older than when she passed Earth. That means she took 20 years to reach planet Y. This is only possible when she traveled with the speed of light

So the velocity v = 300000 KM/Sec.