This preview shows pages 1–6. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Lesson 01 From Modern Physics to Radiation Physics MP 200 Radiation Physics 2010 Duke Medical Physics Graduate Program 1 Introduction In order to study Radiation Physics in detail, we need a knowledge of: • Classical mechanics, • Special theory of relativity and, • Quantum physics. In this lesson, we briefly cover the some of the materials that we need to understand the Radiation Physics. Revision of Classical Mechanics • Subject that developed by Isaac Newton and other contemporary physicists. • Related to objects moving with speeds <<< speed of light. • Governed by Newton’s Laws of Motion Newtons Laws of Motion • First Law: Law of inertia In the Absence of a net force, a body at rest remains at rest, and a body in motion remains in motion with constant velocity. • Second Law: Net force acting on a body or system is proportional to the rate of change of momentum of the body ( system) F = dp dt If mass m is constant, F = m dv dt = ma 2 • Third Law: For every force(action), there is an equal and opposite force(reaction). Work and Energy • For a constant force F , work, W = F.d . where d = distance • For a variable force, W = R F ( r ) .dr • Kinetic energy K = 1 2 mv 2 and potential energy U = mgh h = height from a reference point • Work energy theorem: W = K f K = Δ K K = kinetic energy Conservative and Nonconservative forces • Conservative Force: Work done by the force in moving an object is independent of the objects path. example: gravitational force • Nonconservative Force: Work done by the force, in moving an object depends on the ob jects path. example: frictional force Conservation of Mechanical energy The sum of kinetic energy ( K ) and potential energy ( V ) is called total mechanical energy. 3 For a conservative system, the sum of all kinetic and potential energy is constant, and equals the total mechanical energy of the system. Final total mechanical energy = Initial total mechanical energy 1 2 mv 2 + V = 1 2 mv 2 + V Isolated system and law of conservation of energy • In a closed system or an isolated system, particles can interact with each other, but not with anything outside. • The Law of conservation of total energy: The total energy of an isolated system is always conserved. Power The time rate of doing work is called power. P = W t units: J.s 1 and 1 J.s 1 = 1 Watt Momentum • Linear Momentum p = mv , is a vector quantity. Units: kg.m.s 1 • Conservation of linear momentum: For an isolated system, linear momentum is conserved. i.e. Final linear momentum of the system = Initial linear momen tum p f = p i 4 Revision of Special Theory of Relativity • Event: A Physical happening that occurs at a certain place and time....
View
Full
Document
This note was uploaded on 10/30/2010 for the course MP 200 taught by Professor Guna during the Fall '10 term at Duke.
 Fall '10
 Guna

Click to edit the document details