ME 211 Homework 2 Solutions

ME 211 Homework 2 Solutions

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: weightwillbepulledoppositeand paralleltotheforceoffriction,sothemanshouldbeabletoliftmoreweight.Write thetwoequilibriumequationsinthexandy. F F x y W + 0.6N 3 Answers = 0 = N - 200 =0=- W = 360lbs Problem#74.65 ThehomogeneoussemicylinderhasamassmandmasscenteratG.Determinethe largestangleoftheinclinedplaneuponwhichitrestssothatitdoesnotslipdown theplane.Thecoefficientofstaticfrictionbetweentheplaneandthecylinderis s=0.3.Also,whatistheangleforthiscase? 1.) DrawtheFBD 2.)Writetheequilibriumequationsincludingtheforceoffriction.Tobegin,findthe weightinthexdirectionalongtheinclineandtheyperpendiculartotheincline.Your newaxeswillhavexalongtheinclinedsurfaceandywillbeperpendiculartothat. Frition = N W x :W sin( ) W y :W cos( ) 3.)Nowwritetheequilibriumequations.Sumtheforcesalongtheincline,and sumtheforcesperpendiculartotheincline. F F x y = 0 = -W sin( ) + N = 0 = W cos( ) + N 4.)Youwillnoticethatwehavethreeunknowns,(W,N,and),soweneedto eliminateonetohavetwoequations,andtwounknownstoallowustosolvefor . F F x y = 0 = -W sin( ) + N = 0 = -W cos( ) + N N = W cos( ) 0 = -W sin( ) + (W cos( )) W sin( ) = (W cos( )) sin( ) = cos( ) sin( ) = cos( ) tan( ) = = 16.69 Part(b) 4r r = 3 sin(180 - ) sin(16.7) sin = 0.6771 = 42.6 Problem#84.67 A35kgdiskrestsonaninclinedsurfaceforwhichs=0.2.Determinethemaximum verticalforcePthatmaybeappliedtolinkABwithoutcausingthedisktoslipatC. Part(a) 1.)DrawtheFBD 2.Writetheequilibriumequations F = 0 = A - B F = 0 = -P + A + B M = 0 = P(0.6) - A (0.9) x y x x y y B y Ay = 0.667P Part(b) 1.)DrawtheFBD 2.)Writetheequilibriumequations F = 0 = N sin(60) - A - W - N sin(30) M = 0 = N(0.200) - Ay(0.200) M = 0 = N(0.200) - (0.667P)(0.200) y y O O P= N * .667 N * ) - 35 * 9.81- N sin(30) 0.667 0 = N sin(60) - 0.667( N = 606.6N P = 181.9N F F x y = 0 = -W sin( ) + N = 0 = -W cos( ) + N N = W cos( ) 0 = -W sin( ) + (W cos( )) W sin( ) = (W cos( )) sin( ) = cos( ) sin( ) = cos( ) tan( ) = = 16.69...
View Full Document

This note was uploaded on 05/12/2010 for the course MECHENG 211 taught by Professor ? during the Fall '07 term at University of Michigan.

Ask a homework question - tutors are online