Some of the Egyptian pyramids crumbled because they exceeded the angle of repose (Critical Angle). (static = tan) is the max angle of a ramp can have…

Some of the Egyptian pyramids crumbled because they exceeded the angle of repose (Critical Angle). (μstatic = tanɵ) is the max angle of a ramp can have for an object to remain stationary. Prove this (informal FBD).
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