# Rotation 4

The figure above shows 2 identical planks, each of which makes an angle of $$\theta$$ with the rough horizontal surface. A string holds these 2 planks together at the top.

Given that the coefficient of static friction between each of the planks and the surface is 0.5, find the minimum $$\theta$$ (in degrees, to 1 decimal place) for which the system will remain in an equilibrium state.

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