1. Statics (ENGR 2214) Prof S. Nasseri What you need to know from Physics! ENGR 2214

2. Statics (ENGR 2214) Prof S. Nasseri Definitions Force: Generally considered as a push or a pull exerted by one body on another. Interaction occurs when there is direct contact between the bodies. Gravitational, electrical and magnetic forces do not require direct contact. Force is characterized by magnitude, direction and point of application. Particle: An object having mass but the size is neglected. = m Rigid Body: A combination of a large number of particles which remain in a fixed position relative to each other, both before and after the application of a force.

3. Statics (ENGR 2214) Prof S. Nasseri Newton’s Three Laws of Motion First Law: A particle originally at rest, or moving in a straight line with constant velocity, will remain in this state provided the particle is not subjected to unbalanced forces.

4. Statics (ENGR 2214) Prof S. Nasseri Newton’s first law

5. Statics (ENGR 2214) Prof S. Nasseri Newton’s first law

6. Statics (ENGR 2214) Prof S. Nasseri Newton’s Second Law Second Law: A particle acted upon by an unbalanced force F experiences an acceleration that has the same direction as the force and a magnitude that is directly proportional to the force. If F is applied to a particle of mass m then: F = ma. m

7. Statics (ENGR 2214) Prof S. Nasseri Newton’s Second Law

8. Statics (ENGR 2214) Prof S. Nasseri Third Law: The mutual forces of action and reaction between two particles are equal, opposite and collinear. Newton’s Third Law

9. Statics (ENGR 2214) Prof S. Nasseri Newton’s Third Law

10. Statics (ENGR 2214) Prof S. Nasseri Newton’s Laws of Gravitational Attraction Where: F = force of gravitation, G = universal constant of gravitation G = 6.673 × 10 -11 m 3 kg -1 s -2 m 1, m 2 = masses of two particles, r = distance between two particles.

11. Statics (ENGR 2214) Prof S. Nasseri Newton’s Laws of Gravitational Attraction According to this law, an object's weight is defined by: in which: m = mass of object M = mass of earth r = distance from center of earth to particle g= 9.81 m.s -2 (determined at sea level and at a latitude of 45 o which is considered “standard location”).