Introduction to Mechanics

INTRODUCTION

Mechanics is defined as “A science which deals with the laws and principle of mechanics.” Engineering Mechanics is the application of laws of mechanics to engineering problems.

                                      CLASSIFICATION OF ENGINEERING MECHANICS

• Particle is a point mass. If the dimension of body can be ignored while studying its equilibrium or motion, it may be treated as a particle

• Rigid body: - A body said to be rigid if it does not change its shape and size under the influence of forces acting over it. In rigid body the distance between to particle remains same before and after loading.

• Force: - Force is the external agent which changes or tends to change the state of rest or of motion of a body in a straight line. Force is the vector quantity.

• Effects of force

1. It may change the motion of body. The motion may be accelerated or retarded.
2. It may bring body in equilibrium under unbalance forces are already acting over it.
3. It may change the shape and size of the body.

• Characteristics of force

1. Magnitude
2. Direction
3. Sense of nature
4. Point of application

• System of forces: -

1. Co-planar forces : -The forces, whose line of action lie on the same plane.
2. Co-linear forces: -The forces, whose line of action lie on the same line.
3. Concurrent forces: -The forces, meet at one point. 
4. Co-planar concurrent forces: -The forces, whose line of action lie on a plane and meet at one point on the same plane.
5. Co-planar non-concurrent forces: -The forces, whose line of action lie on a plane and do not meet at one point on the same plane.
6. Non-coplanar non-concurrent forces: -The forces, which do not meet at one point and their line of action of do not lies on the same plane.