Let’s say ISRO discovered life on a planet which is 40 light years away from Earth. So it sent a spacecraft to verify the discovery. The spacecraft can travel with a maximum speed of 70 lightyears/year ( using a Wormhole!) and any change in speed is instantaneous (i.e. time lost in acceleration and deceleration is negligible). At the midway crew members realized that they were traveling at the speed of 20 lightyears/year and decided to speed up the spacecraft. How fast do they need to travel the rest of the course to have an average speed of 40 lightyears/year? Given the speed limits of the spacecraft is it even possible?!
Its impossible to have an average speed of 40 lightyears/year.
In order to have an average speed of 40 lightyears/year the crew needs
to travel the course within a year. But by travelling halfway of the
course at 20 lightyears/year, the crew has already spent a year. So no
matter how fast they travel the total time would be more than a year.(2mins).