Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Resultant of Forces

Description

This lecture introduces the concept of resultant force and explains how to calculate the resultant of two concurrent forces. The instructor demonstrates how to determine the position of the resultant force's line of action using vector addition and force polygons.

Official source

Related concepts (22)

Resultant force

In physics and engineering, a resultant force is the single force and associated torque obtained by combining a system of forces and torques acting on a rigid body via vector addition. The defining feature of a resultant force, or resultant force-torque, is that it has the same effect on the rigid body as the original system of forces. Calculating and visualizing the resultant force on a body is done through computational analysis, or (in the case of sufficiently simple systems) a free body diagram.

Force

In physics, a force is an influence that can cause an object to change its velocity, i.e., to accelerate, unless counterbalanced by other forces. The concept of force makes the everyday notion of pushing or pulling mathematically precise. Because the magnitude and direction of a force are both important, force is a vector quantity. It is measured in the SI unit of newton (N) and often represented by the symbol F.

Free body diagram

In physics and engineering, a free body diagram (FBD; also called a force diagram) is a graphical illustration used to visualize the applied forces, moments, and resulting reactions on a body in a given condition. It depicts a body or connected bodies with all the applied forces and moments, and reactions, which act on the body(ies). The body may consist of multiple internal members (such as a truss), or be a compact body (such as a beam). A series of free bodies and other diagrams may be necessary to solve complex problems.

Net force

In mechanics, the net force is the sum of all the forces acting on an object. For example, if two forces are acting upon an object in opposite directions, and one force is greater than the other, the forces can be replaced with a single force that is the difference of the greater and smaller force. That force is the net force. When forces act upon an object, they change its acceleration. The net force is the combined effect of all the forces on the object's acceleration, as described by Newton's second law of motion.

Line of action

In physics, the line of action (also called line of application) of a force (F) is a geometric representation of how the force is applied. It is the line through the point at which the force is applied in the same direction as the vector . The concept is essential, for instance, for understanding the net effect of multiple forces applied to a body. For example, if two forces of equal magnitude act upon a rigid body along the same line of action but in opposite directions, they cancel and have no net effect.

Related lectures (32)

Auxiliary Cable Method

Explores the auxiliary cable method for calculating resultant forces in arbitrary systems using cable constructions and intersections.

Resultant: Amplitude and Orientation

Explores the resultant force calculation, cable networks design, arch stability, and pretension systems in structural engineering.

Cable Forces and Resultant: Analysis and Applications

Explores the analysis of cable forces and resultant using graphical methods and applets.

Hydrostatic Forces: Recap and Applications

Covers hydrostatic forces, forces on submerged surfaces, and centroids.

Pressure Calculation and Forces on Submerged Surfaces