Fundamental Concepts Of Mechanics q6b6f

Fundamental concepts of Mechanics There are four fundamental concepts of mechanics Space Time Mass Force It is difficult to define these four concepts. These concepts accepted on the basis of our experiences and used as a reference of study of mechanics. Space Space is concern with the position of a body to fix the position of a point or origin. Mass To distinguish behavior of the two bodies under the action of an identical force. Time Time mostly used in dynamics to relate the sequence of events. To define an event it is not enough to indicate its position in space. Event time should also be given Force Force s an essential action which changes or tends to change the state of rest or uniform motion of body. Fundamental Principles of Mechanics There are six fundamental principles of Mechanics 1. Law of parallelogram of forces

2. 3. 4. 5. 6.

Law of transmissibility Newton's first law of motion Newton's first law of motion Newton's third law of motions Newton's law of universal gravitation

   Law of parallelogram of forces When two forces acting on a particle may be replaced by a single force, called resultant of two forces. This is obtained by drawing the diagonal of parallelogram, The sides of parallelogram equal to the given forces.  Law of transmissibility This law states that conditions of equilibrium or motion of rigid body will remain unchanged if a force acting at a given point of the rigid body is replaced by a force of the same magnitude and the same direction, but acting at different points. These two forces have the same line of action.    Newton's first law of motion If all the resultant forces acting on a particle is zero, the particle will remain at rest if originally at rest or will be in motion with constant speed in a straight line if originally in motion.  Newton's second law of motion If all the resultant forces acting on a particle is zero, The particle will have the acceleration proportional to the magnitude of the resultant in the direction of this resultant forces F

=

ma

   Newton's third law of motions

The forces of action and reaction between bodies in have the same magnitude, same line of action and in opposite sense.    Newton's law of universal gravitation When two particles of mass m1 and m2 are attracted mutually with equal and opposite forces F and -F of magnitude F as by formula F=G

m1m2/r2

What is Mechanics The branch of physical science that deals with energy and forces, and their effects on bodies. OR Mechanics is a science that describes or predicts condition of rest and motion under the action of forces. Particle It means a very small amount of matter. It is assumed to occupy a single point in space.

Rigid body it is a combination of many particles occupying fixed positions with respect to each other.