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[parent] polar coordinate motion example of generalized coordinates (Example)

As an example let us get the equations in polar coordinates for motion in a plane

Here

x = r cosϕ,    y = r sin ϕ

˙x2 + ˙y2 = v2 = ˙r2 + r2ϕ˙2

and

     m- [ 2    2 ˙2]
T  =  2  ˙r +  r ϕ

∂T- = m r˙
∂ ˙r

∂T-=  mr ˙ϕ2.
∂r

                2
δrW  =  m [¨r − rϕ˙]δr = R δr

if R is the impressed force resolved along the radius vector.

∂T-      2 ˙
  ˙=  mr  ϕ,
∂ϕ

∂T
--- = 0.
∂ϕ

          d   2
δϕW  = m  --(r ˙ϕ)δϕ = Φr δϕ
          dt

if Φ is the impressed force resolved perpendicular to the radius vector.

In a more familiar form

  [                ]
    d2r    ( dϕ )2
m   --2-− r  ---     = R,
    dt        dt

     (      )
m- d-   2d-ϕ
 r dt  r  dt  =  Φ.

"polar coordinate motion example of generalized coordinates" is owned by bloftin.
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Cross-references: radius vector, force, motion

This is version 2 of polar coordinate motion example of generalized coordinates, born on 2008-07-18, modified 2008-07-21.
Object id is 287, canonical name is PolarCoordinateMotionExampleOfGeneralizedCoordinates.
Accessed 1806 times total.

Classification:
Physics Classification45.20.Jj (Lagrangian and Hamiltonian mechanics)
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