## 9 January 2018

### System of forces

When a mechanics problem or system has more than one force act on a body, it is known as a system of force OR Force system.

There is a various system of forces following below :
1. Coplanar forces: The forces, whose line of action lie on the same plane that is known as coplaner forces.

There are four types of coplanar forces system :
• Collinear force system: When the lines of action of all the forces of a system act along the same line, this force system is called collinear force system.
• Parallel force system: When the line of action of all the forces of a system is different and parallel to each other, this force system is called a parallel force system.
• Concurrent force system: When the forces extended and it passes through a single point this system is called the concurrent force system.
The point is called the point of concurrency. The lines of actions of all forces meet at the point of concurrency.
Concurrent forces may or may not be coplanar.

• Non-concurrent force system: In the system, all the forces do meet at a common point of concurrency, this force system is called non-concurrent force system.

Parallel forces are an example of this type of force system.
Non-concurrent forces may be coplanar or non-coplanar.

2. Non-coplanar forces: The forces, whose line of action don't lie on a single plane is called non-coplanar forces or Space forces.

There is three non-coplanar force system :
• Parallel force system: When the line of action of all the forces of a system is different and parallel to each other and also both are in a different plane, this force system is called parallel force system.
• Non-coplanar concurrent forces: When all the forces in the system meet at one point but their lines of action don't lie on the same plane that type of system is known as non-coplanar concurrent forces.
• Non-coplanar non-concurrent forces : The forces that are not meet at one point and their lines of actions do not lie on the same plane are called non-coplanar non-concurrent forces.