Question

Equilibrium is not established for _ and reaction acting at two _points​

Answer 1

Answer:

There are many types of structural elements. It was seen in an earlier lecture that the support condition has a significant influence on the behavior of the specific element. It is advantagous to identify certain types of structural elements which have distinct characteristics. If an element has pins or hinge supports at both ends and carries no load in-between, it is called a two-force member. These elements can only have two forces acting upon them at their hinges. If only two forces act on a body that is in equilibrium, then they must be equal in magnitude, co-linear and opposite in sense. This is known as the two-force principle. The two-force principle applies to ANY member or structure that has only two forces acting on it. This is easily determined by simply counting the number of places where forces act on that member. (REMEMBER: reactions are considered to be forces!) If they act in two places, it is a two-force member.

One of the unique aspects of these members is the fact that the line of action of the resultants of the forces acting on the two ends of the member MUST pass along the center line of the structural element. If they did not, the element would not be in equilibrium! Thus, even if a loading exists at either end that consists of only one of the components (i.e. Fx or y), the resultant of all of the forces acting on the two-force member passes through the center line of the member.

Most, but not all, two-force members are straight. Straight elements are usually subjected to either tension or compression. Those members of other geometries will have bending across (or inside) their section in addition to tension or compression, but the two-force principle still applies. There are NO EXCEPTIONS!!!

Some common examples of two-force members are columns, struts, hangers, braces, pinned truss elements, chains, and cable-stayed suspension systems. What are some others?

I hope this answer is help you

thanks

Answer 2

Explanation:

In classical mechanics, a particle is in mechanical equilibrium if the net force on that particle is zero.[1]:39 By extension, a physical system made up of many parts is in mechanical equilibrium if the net force on each of its individual parts is zero.[1]:45–46[2]

In addition to defining mechanical equilibrium in terms of force, there are many alternative definitions for mechanical equilibrium which are all mathematically equivalent. In terms of momentum, a system is in equilibrium if the momentum of its parts is all constant. In terms of velocity, the system is in equilibrium if velocity is constant. In a rotational mechanical equilibrium the angular momentum of the object is conserved and the net torque is zero.[2] More generally in conservative systems