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Unformatted text preview: Midterm prep • Check the room and place number on the web • Don’t forget your id • Check web later today for makeup room and time • Check review slides online already • Work on the old midterm • Go to help centre or come and see me F ( 29 cos F θ d θ d F = ( 29 cos F θ =the component of F in the d direction Work and energy ( 29 W=Fcos d θ The unit of work =Newton meter =Joule This is a measure of energy F d The work to move a mass up an incline n θ g Mg = F θ + v e y + v e x cos( ) Mg θ sin( ) Mg θ What is the work done to push a mass a distance d up a frictionless incline without accelerating it? x F Ma = = ∑ sin( ) Mg F θ = sin( ) F Mg θ = W = F.d sin( ) W dMg θ = h sin( ) h d θ = W Mgh = The work done depends only on h The work can be retrieved and is called potential energy Conservative forces Conservative force: A force in which the work done in getting from A to B is independent of the path Gravity is a conservative force A B Kinetic Energy and net work F x ∆ υ f υ W F x = ∆ F Ma = ∑ 2 2 2 f a x υ υ = + ∆ 2 2 2 f a x υ υ = ∆ 2 2 2 f F M x υ υ = ∆ ∑ 2 2 1 1 2 2 f F x M M υ υ ∆ = ∑ 2 1 2 M υ = Kinetic energy Net force 2 2 2 f a x υ υ ∆ = Relationship between Work and Kinetic energy F x ∆ υ f υ net f W KE KE = 2 2 1 1 2 2 f F x M M υ υ ∆ = ∑ F x ∆ ∑ = net work net W KE = ∆ F...
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This note was uploaded on 04/07/2012 for the course PHYS 111 taught by Professor Dr.jackman during the Fall '07 term at Waterloo.
 Fall '07
 Dr.Jackman
 Physics, Energy, Work

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