This document discusses static equilibrium and the conditions required for an object to be in equilibrium. It defines equilibrium as a state where the object experiences no change in its motion or internal energy over time. For an object to be in static equilibrium, two conditions must be met: 1) Translational equilibrium - the sum of all forces acting on the object must equal zero. This can be resolved into horizontal and vertical components. 2) Rotational equilibrium - the sum of all torques acting on the object about any point must equal zero. The document provides examples of forces acting on objects in equilibrium and sample problems to solve. It explains that if the net force on an object is nonzero, it will accelerate, but if