Static Equilibrium, Elasticity, and Torque

Torque is the force that causes objects to turn or rotate (i.e., the tendency of a force to rotate an object about an axis).

The first condition of equilibrium is that the net force in all directions must be zero.

The second condition of static equilibrium says that the net torque acting on the object must be zero.

In equilibrium, the net force and torque in any particular direction equal zero.

An object in static equilibrium remains in the same state forever, but not all forms of equilibrium are the same.

When solving static problems, you need to identify all forces and torques, confirm directions, solve equations, and check the results.

A simple machine is a device that changes the direction of a force or augments a force; simple machines fall into six categories.

Arches and domes are structures that exhibit structural strength and can span large areas with no intermediate supports.

Most skeletal muscles and joints exert much larger forces within the body than the limbs will apply to the outside world.

Elasticity is a measure of how much an object deforms (strain) when a given stress (force) is applied.

Fracture is caused by a strain placed on an object such that it deforms beyond its elastic limit and breaks.

The center of gravity is read mathematically as: 'the position of the center of mass and weighted average of the position of the particles'.

Torque is equal to the moment of inertia times the angular acceleration.