BCGBC4010A Apply structural principles to residential low-rise constructions

Structural principles - Forces

Statics

Statics activity
Match the following three equations with the appropriate sentences.
Equations
•	 Fv = 0
•	 M = 0
•	 Fh = 0
Sentences
•	The sum of all vertical forces in the system must be zero
•	The sum of all horizontal forces in the system must be zero
•	The sum of all moments in the system must be zero
The correct answers are:
•	The sum of all vertical forces in the system must be zero,  Fv = 0
•	The sum of all horizontal forces in the system must be zero,  Fh = 0
•	The sum of all moments in the system must be zero,  M = 0
If any of these equations do not hold true in any given situation the system is not in equilibrium. This means it is moving in some direction. The moving system must be made static by the addition of one or more forces.
The resultant force is the force which can be used to replace all the other forces in the system without changing the net effect in the system.
The reaction is the force required to make the system static. The reaction is equal and opposite to the resultant. These forces can be found by using vectors to resolve (or balance) the forces in the system. 

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