- #1

- 890

- 39

## Homework Statement

## Homework Equations

## The Attempt at a Solution

When the plank leavs the wall at angle ##\theta ##,

Torque about ground ## \tau _g = mgl \cos \theta = \frac { m(2l)^2 \alpha }3##

Torque about COM ## \tau _c = Nl =\frac { m(2l)^2 \alpha } {12} ##

Acceleration of COM: a = ## [g^2 +( \frac N m )^2 - 2 g \frac N m \cos \theta]^{0.5} = \alpha l ##

Is this correct so far?

I think the last eqn. is wrong as further calculation gives ##\cos \theta =1##

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