D’Alembert Method

∑ F−I I=0

Contoh :

Free Body Diagram :

Aplikasikan hukum II Newton :

P (t )−f D−f S=m ∙a

mu+f D+ f S=P (t )

mu+c u+ku=P (t )

D’Alembert -> P (t )−f D−f S−I I=0

fs

fD

θ

U2Fs1Fs2

U1

Contoh 2 :

Free Body Diagram :

∑M−I θ=0

−f s2 ∙14l−f s1 ∙

34l−I θ=0

tanθ= ul4

→u1=lθ4

tanθ= u3 l4

→u1=3 lθ4

−3 k ( l4 θ) ∙ 14 l−k (3 lθ4 )∙ 34 l−I θ=034k l2θ+ I θ=0