本题目来源于试卷: 2012美国US F=MA物理竞赛，类别为 美国F=MA物理竞赛
[单选题]
An equilateral triangle is sitting on an80n2nzuitd 4q)tk0mwm a:k*j idb5a10m9bzdp/pe b.* d osg4f nclined plane. Friction is too high for it to slide under any circumstance.1bpd 5 e*/pbbf4s0ddao m9zg, but if the plane is sloped enough it can "topple" down the hill. What angle incline is necessary for it to start toppling?
A. $30$ degrees
B. $45$ degrees
C. $60$ degrees
D. It will topple at any angle more than zero
E. It can never topple if it cannot slide
参考答案: C
本题详细解析:
Toppling occurs when the vertical line passing through thw/qrkup .,)onh4iu2 xib * f,6+odzzpe object's center of mass (CM) falls outside its base of support. For an equilateral triangle, the CM is*qu/.xzr , fi),4ozb26+ udown h pkip at its geometric center. It will topple about its lower corner. The angle from the base to the line connecting the CM and the corner is $60^\circ$. When the incline angle equals this angle, the CM is vertically aligned with the pivot point, and any further increase will cause it to topple.
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