Question

define concurrent forces

Answer 1

The definition of concurrent forces is two or more forces  acting in conjunction with one another at a single location. They do not have the same line of force but pass through a common point. A line of force is defined as the straight line extending for an indefinite period through the point of applying a force and along the direction of force. The opposite of concurrent force is the collinear force , which has the same line of force and may act in the same direction or in opposite diresctions.
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concurrent forces act on a single point, so they can be represented by a single net force acting at a point.

Answer 2

Concurrent forces are three or more forces acting on a body at the same point of application.

If 3 concurrent forces are in one plane and are keeping the body in equilibrium, then the forces can be represented by sides of a triangle.

Then Force1 / Sin A = Force2 / Sin B = Force / Sin C
A, B, C are the angles between forces. A between Force2 and force3.  B between force 1 and force 3.

When a load is suspended at P, the middle of a string which is tied on both ends to nails fixed in wall at the same height, the forces of tension and weight are concurrent forces acting at P. Problem is solved using the above equalities.

If the body is not in equilibrium and is moving with an acceleration, then the net force of the concurrent forces causes the acceleration.