A. 鐗╃悊涓閬撹$畻棰橈紒锛佸湪绾跨瓑锛孲OS~~
鍔涘仛鍔焀F=FL=30*6=180J鍔胯兘Ep=Gh=60*2=120J鏁堢巼=WF/Ep=120/180=2/3=66.6%鎽╂摝鍔沠=(WF-Ep)/L=(180-120)/6=10N绛旓細鎷夊姏鍋氬姛180J锛屾満姊版晥鐜66.6%锛屾懇鎿﹀姏f涓10N