When several forces of different magnitude and direction act upon a body,
they constitute a system of forces.
If all the forces in a system lie in a single plane known as coplanar force system.
If the line of action of all the forces in a system passes through a single point it is called
a concurrent force system.
In a system of parallel forces, all the forces are parallel to each other.
If the line of action of all the forces lies along a single line then it is known
as a collinear force system.
