Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.

Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer.

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.