Legend

 F = Force

Equilibrium

Previous chapters examined forces that were unbalanced, resulting in acceleration, change in direction or speed.   Equilibrium analyzes forces on objects or systems that are balanced, thus the objects or systems are at rest or moving at a constant velocity.

For example, all houses, buildings, free-standing structures stay together and stay standing because a great number of forces were taken into consideration and balanced correctly by engineers and architects using principles of equilibrium (also known as statics).

When analyzing any equilibrium problem, three conditions must be true:

 1) Fx = 0 2) Fy = 0 3) = 0 1) all horizontal forces add up to zero 2) all vertical forces add up to zero 3) all twisting, rotating forces add up to zero (called torque, )

Solving equilibrium problems uses most of the concepts we have learned so far (vectors, dynamics, free-body diagrams, Newton's laws).  It is a new way of using old techniques.
 Momentum Translational