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General Principles. Modeling of problem Newton’s Law of Motion Law of Gravitation Units Vectors. Problem Solving Strategy:. Physical Model: Transformation of actual problem into simpler Assumptions Using Free Body Diagram : FBD Mathematical Model: Newton’s Law:
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General Principles • Modeling of problem • Newton’s Law of Motion • Law of Gravitation • Units • Vectors
Problem Solving Strategy: • Physical Model: • Transformation of actual problem into simpler • Assumptions • Using Free Body Diagram: FBD • Mathematical Model: • Newton’s Law: • F=0 and Mo=0 (coord. System) • Set of equations to be solved • Solution of Equations: • Computational Tools: Maple, Matlab, Prog. • Interpretation Results: Does answ. Makes sense?
Newton’s Laws of Motion Law #1: Body is in Equilibrium Body will remain at rest or continue to move with same speed (accel.=0) and direction unless unbalance force is acted on body or particle.
Newton’s Law of Motion Law #2: Non-equilibrium Change of motion of a body is proportional to the next force imposed on the body and is in direction of net force.
Newton’s Law of Motion • Law #3: Action & Reaction If one body exerts a force on a second body, then second body exerts a force on the first body that is equal in magnitude, opposite in direction and collinear (same line of action).
Law#4: Law of Gravitation • Any two bodies are attracted to each other with a force whose magnitude is proportional to the product of their gravitational masses and inversely proportional to the square of the distance between them. m F M F r
Activity 1: Weight • If an object has a mass m=50Kg find the weight of object at surface of earth, moon and sun? G = 66.73x10-12 (m3/Kg/s2) Universal gravitational const. Given: • Mass of earth= 5.976x1024 Kg • Mass of moon= 7.35x1022 Kg • Mass of sun=1.99x1030 Kg • Radius of earth=6.371x106 m • Radius of Moon: 1.738x10^6 m • Radius of Sun: 6.96x10^8 m
Weight & Mass: • Weight: where: and on earth surface: g= 9.807m/s2 (SI) or g= 32.17 ft/s2 (US) • Mass:
Units Tables 1.6 and 1.7 in book
Percent Error A = Value to be Compared B = Reference Value % Error = (A-B)/B (100%)