When I was searching for information about ''which is vs being'', I found information about this topic. It said that using ''which is'' '' is not idiomatic to use in the following sentence;
sentence a)"Various assumptions must be made during the course of a force analysis reflecting the specific characteristics of the particular system being investigated" _____correct one.
sentence b) "Various assumptions must be made during the course of a force analysis reflecting the specific characteristics of the particular system which is investigated" _______incorrect one
If someone can explain that situation (why ''being'' correct ,''which is'' incorrect? )
I will be thankful.