李智英
後面那段承重面有點不太對…粗糙能立起來跟承重面無關，而是重力形成的力矩和（未知最大）靜摩擦力的力矩抵消，形成靜止。
So… 更多 the last portion of explanation was a bit weird. Think it this way: the torques generated from gravity and friction would have opposite direction(by R.H.R) but with same magnitude to cancel out each other, and thus reach the equilibrium you saw in video.
