Applied mechanics or Engineering mechanics is a branch of the physical sciences and the practical application of mechanics.

Pure mechanics describes the response of bodies or systems of bodies to external behavior of a body, in either a beginning state of rest or of motion, subjected to the action of forces.

Q. What is Force ?

Force , It may be defined as an agent which produce or tends to produce or destroy tends to destroy the motion of body.

It may be consider for:

• Change of motion of the body
• Retard the motion of the body
• Balance the forces which acts on the body
• Give rise the internal forces in the body.

The characteristics of the forces are:

• Nature of the force (Push or Pull)
• Line of action of the force
• Point at which the force acts on the body
• Magnitude of the force

S.I. Unit of the force is Newton(N). 1kgf = 9.81N

Q. What is Resultant Force ?

Resultant force is a single force which produce the same effect as produce by all the force acts on the body.

Resultant force can be found out by following method:

• Parallelogram Law
• Triangle Law
• Polygon Law

Q. The angle between two forces when the resultant is maximum and minimum respectively are:

0 and 180 degree.

Q. Concurrent forces are those forces whose lines of action:

meet at one point.

Q. If the resultant forces acting on a body is zero, then the body will be in Equilibrium. (Yes/No)

Yes.

Q. Process of finding out the resultant force is called _________ of the force?

Composition of the force.

Q. what are Coplaner Forces ?

Coplaner forces are those force whose line of action lies in the same plane.

Q. Define Lami’s Theorem ?

If three coplaner force acting on a point are in equilibrium, then each force is proportional to the sine angle between the other two forces.

Q. The Moment of a force?

• The moment of force is the turning effect produced by a force, on the body, on which it acts.
• The moment of force is equal to the product of the force acting on the body and the perpendicular distance of a point and the line of action of the force.
• The moment of a force is equal to twice area of a triangle, whose base is the line representing the force and whose vertex is the point, about which the moment is taken.

Q. What is Varingon’s Theorem ?

The algebraic sum of their moments about the any point is equal to the moment of the resultant force about the same point.