| Inertia: | (english) The tendency of an object at rest to remain at rest, and of an object in motion to remain in motion. |
| Inertial Force: | (english) A fictitious force used for convenience in visualizing the effects of forces on bodies in motion. For an accelerating body, the inertial force is considered as a body force whose resultant acts at the object's center of gravity in a direction opposite the acceleration. The magnitude of the force is the mass of the object times the magnitude of the acceleration. |
| Internal force: | (english) Forces which hold an object together when external forces or other loads are applied. Internal forces are sometimes called resisting forces since they resist the effects of external forces. |
| Kinetic Energy: | (english) The energy of a moving mass; equal to (mv^2)2. Where m is mass and v is the magnitude of the velocity. |
| Linear: | (english) A structure is said to behave linearly when its the deformation response is directly proportional to the loading (i.e. doubling the load doubles the displacement response). For a material, linear means that the stress is directly proportional to the strain. |
| Line of Action: | (english) The line of action of a force is the infinite line defined by extending along the direction of the force from the point where the force acts. |
| Mass: | (english) A property of an object measured by the degree that it resists acceleration. |
| Magnitude: | (english) A scalar value having physical units. |
| Modulus of elasticity: | (english) The proportional constant between stress and strain for material with linear elastic behavior: calculated as stress divided by strain. Modulus of elasticity can be interpreted as the slope of the stress-strain graph. It is usually denoted as E, sometimes known as Young's Modulus Y, or E-Modulus. |
| Moment: | (english) The resultant of a system of forces causing rotation without translation. A moment can be expressed as a couple. |