BT204 Static Machnic RGPV 1st year students

1st year student RGPV university

1. Statika STRUKTUR |MEU 2303 P (Statics) Berli Kamiel, Ph.D Week #1

2. Mechanics Mechanics is a branch of the physical sciences that is concerned with the state of rest or motion of bodies that are subjected to the action of forces. In general, mechanics may be divided into three branches:

3. Rigid-body mechanics is a basic requirement for the study of the mechanics of deformable bodies and the mechanics of fluids. Furthermore, rigid-body mechanics is subdivided into: Statics deals with the equilibrium of bodies, that is, those that are either at rest or move with a constant velocity; Dynamics is concerned with the accelerated motion of bodies. We will study this guy in this unit! We will discuss this in the other units (Kinematics and Dynamics)

4. Fundamental Concepts Before we start our study in engineering mechanics, it is critical to understand the meaning of several fundamental concepts and principles. Length is used to locate the position of a point in space and thereby describe the size of a physical system Time is conceived as a succession of events Mass is a measure of a quantity of matter that is used to compare the action of one body with that of another In general, force is considered as a “push” or “pull” exerted by one body on another

5. Fundamental Concepts ( continued) A particle has a mass, but a size that can be neglected. Examples ? A rigid body can be considered as a combination of a large number of particles in which all the particles remain at a fixed distance from one another, both before and after applying a load A concentrated force represents the effect of a loading which is assumed to act at a point on a body

6. For any force analysis, we can assume the hook as a particle. We may consider the steel railroad wheel as a rigid body since it does not deform very much under load and the force acting on it can be considered as a concentrated load.

7. Fundamental Concepts ( continued) Newton’s Three Laws of Motion

8. Fundamental Concepts ( continued) Newton’s Three Laws of Motion

9. Fundamental Concepts ( continued) Newton’s Three Laws of Motion We will use Newton’s first and third law extensively in statics!

10. Fundamental Concepts ( continued) Units of Measurement The four basic quantities are NOT all independent from one another. They are related by Newton’s second law; F =m a Because of this, the units used to measure these quantities cannot ALL be selected arbitrarily

11. Fundamental Concepts ( continued) Units of Measurement In consequence, F =m a is maintained ONLY IF The three of the four units, called based units are DEFINED And then the fourth unit is DERIVED from equation

12. Fundamental Concepts ( continued) SI Units Defined/based units Force in Newton (N) derived from F =m a Derived unit N = kg.m /s 2 g= 9.81 m/s 2

13. Fundamental Concepts ( continued) U.S. Customary (FPS) Defined/based units Mass in slug derived from F =m a Derived unit slug = lb.s 2 / ft g= 32.2 ft /s 2

14. Fundamental Concepts ( continued)

15. Fundamental Concepts ( continued) Prefixes

16. Fundamental Concepts ( continued) Conversion of Units

17. Fundamental Concepts ( continued) Dimensional Homogeneity Each term of any equation used to describe a physical process must be expressed in the same units s = vt + ½ at 2 prove that each term has the same units !

18. “The most effective way of learning the principles of engineering mechanics is to solve problems ” ( R.C. Hibbeler )

19. Examples

20. Selected Problems

21. Selected Problems

22. Selected Problems All materials for these slides were taken after some modifications from “Engineering Mechanics, Statics and Dynamics, twelfth edition, R.C. Hibbeler ”