What is concurrent forces in space?

Answer 1

When all the forces of a force system act in one plane it is called coplanar force system. If the forces act in more than one plane then it is forces in space. In this case forces are not contained in one plane.

When all the forces of a system pass through a common point they are called concurrent forces. Thus we have concurrent coplanar forces when all forces are in one plane and pass through a common point. Also when forces in space pass through a common point we have concurrent forces in space.