I have no idea how to solve this question. Please tell me which physics concept I need to apply here.
The question has been attatched here. There is also a translation of this question in bengali which you can ignore.

1 meter square football field? Must be for teams of ants!

The concept to use is Lorentz contraction, which will take place in the AB (horizontal) direction. There is no contraction in the vertical direction.

Wait a minute. While explaining this to a friend of mine, I realised that AEB and CFD Are also parts of the football field. So, how do I calculate the area of a field with the two semi circles having Lorentz contraction on one dimension only?

First calculate the original (uncontracted) area. With contraction applied in one direction only the new area = original area times the contraction factor.

Thanks!

Thanks!