同学们在操场上进行爬杆比赛，使他们能够上升的力是（ ）A．重力B．压力C．摩擦力D．拉 一个运动员正在进行爬杆训练，若杆是竖直放置的，则使运动员上升...
\u4e00\u4e2a\u8fd0\u52a8\u5458\u6b63\u5728\u8fdb\u884c\u722c\u6746\u8bad\u7ec3\uff0c\u82e5\u6746\u662f\u7ad6\u76f4\u653e\u7f6e\u7684\uff0c\u5219\u4f7f\u8fd0\u52a8\u5458\u4e0a\u5347\u7684\u529b\u662f\uff08\u3000\u3000\uff09A\uff0e\u91cd\u529bB\uff0e\u4eba\u5bf9\u81ea\u5df1\u7684\u4f5c\u7528\u8fd0\u52a8\u5458\u5728\u6746\u4e0a\u53d7\u5411\u4e0b\u7684\u91cd\u529b\uff0c\u624b\u53d7\u6746\u4e0e\u6746\u5782\u76f4\u7684\u538b\u529b\uff0c\u56e0\u4e3a\u548c\u6746\u4e4b\u95f4\u6709\u538b\u529b\u5219\u53ef\u4ea7\u751f\u5411\u4e0a\u7684\u6469\u64e6\u529b\uff0c\u6b63\u662f\u6469\u64e6\u529b\u4e3a\u8fd0\u52a8\u5458\u63d0\u4f9br\u4e0a\u5347\u6240\u9700\u8981\u7684\u529b\uff0e\u6545\u9009D\uff0e
\u8fd0\u52a8\u5458\u5728\u6746\u4e0a\u53d7\u5411\u4e0b\u7684\u91cd\u529b\uff0c\u624b\u53d7\u6746\u4e0e\u6746\u5782\u76f4\u7684\u538b\u529b\uff0c\u56e0\u4e3a\u548c\u6746\u4e4b\u95f4\u6709\u538b\u529b\u5219\u53ef\u4ea7\u751f\u5411\u4e0a\u7684\u6469\u64e6\u529b\uff0c\u6b63\u662f\u6469\u64e6\u529b\u4e3a\u8fd0\u52a8\u5458\u63d0\u4f9b\u4e86\u4e0a\u5347\u6240\u9700\u8981\u7684\u529b\uff0e\u6545\u9009B\uff0e
∵人在爬杆（接近匀速）时，受重力和摩擦力一对平衡力的作用，重力的方向竖直向下，∴摩擦力的方向竖直向上，
∴使人能上升的力只能是摩擦力．
故选C．
绛旓細鐖潌浼樼浣滄枃1 鑷粠涓婁簡5骞寸骇锛屾垜浠椿鍔ㄧ殑鏃堕棿瓒婃潵瓒婂皯銆傛墍浠ワ紝姣忔槦鏈熺殑浣撹偛璇炬垚浜嗘垜浠殑鏈鐖便傚惉鍚屽浠锛岃繖鑺備綋鑲茶鎴戜滑鐖潌锛鎴戠湡鏈変簺绱у紶锛屾垜鍙粠鏉ユ病鏈夌埇杩囨潌銆傛曚粈涔堬紝杩欏緢绠鍗曘傜瓑浼氬効锛岀湅鎴戠殑'锛鍚屽浠湪鎿嶅満涓浣犱竴瑷鎴戜竴璇湴璋堣锛屼竴涓釜纾ㄦ嫵鎿︽帉锛岃穬璺冩璇曘傝鎴戝厛鏉ュ仛绀鸿寖銆
绛旓細骞冲潎閫熷害澶氬皯锛熸寜鐓1绠楃殑銆傝繃绋嬩竴鏍 璁鏉闀縇锛氫笂鏉嗘椂闂达細t1=L/2 涓嬫潌鏃堕棿锛歵2=L/V涓 骞冲潎閫熷害1=2L/锛坱1 + t2锛1=2L/锛圠/2 + L/V涓嬶級V涓=2/3m/s=2.4km/h
绛旓細鎵鐢ㄦ椂闂翠箣姣斾负 t 鐢 t 涔 = 9s 10s = 9 10 锛涙墍浠ョ敳銆佷箼浜屼汉鐖潌鐨勫姛鐜囦箣姣旀槸 P 鐢 P 涔 = W 鐢 t 鐢 W 涔 t 涔 = W 鐢 W 涔 脳 t 涔 t 鐢 = 5 ...
绛旓細P=f*v;Va:Vb=Tb:Ta=5:4;鑰屼粬浠殑璐ㄩ噺涓鏍凤紝鎵浠a:Pb=5:4;鍙﹁В 浠栦滑璐ㄩ噺涓鏍凤紝鐖埌鍚屼竴楂樺害鎵鍋氱殑鍔熶竴鏍凤紝鍗砏a=Wb;W=P*T;鎵浠a:Pb=5:4;閫堿
绛旓細鐖潌姣旇禌瑙勫垯鍜岃姹 1銆侀夋墜鍦ㄨ禌鍓嶏紝姣忎汉鍙粌涔1~2娆★紝姣旇禌杩囩▼涓紝涓嶈兘鍊熷姪鍏跺畠璁惧锛岃姹傛槸寰掓墜鐖潌锛2銆佺埇鏉嗘椂浠庝笅鍒颁笂锛鎵嬩竴瀹氳鎽稿埌鏉嗛《鐨勫皬绾㈡棗鎵嶆湁鏁堬紱3銆佹椂闂存瘡浜1鍒嗛挓锛岀敤鏃惰秺灏戯紝鍚嶆闈犲墠銆傚湪1鍒嗛挓鍐咃紝濡傝惤鍦帮紝鍙噸澶嶇埇鏉嗐傚弬鑰冭祫鏂欙細http://rlstyj.blog.163.com/blog/static/1089...
绛旓細绔块暱鐩稿悓锛岀敳鐢10绉掞紝涔欑敤9绉掞紝鐢蹭箼鐨勪綋閲嶄箣姣旀槸5姣6锛屽仛鍔熶箣姣斾负5姣6锛岄偅涔堜袱浜虹殑骞冲潎鍔熺巼姣斾负锛氾紙5/10锛夛細锛6/9锛=锛1/2锛/锛2/3锛=3锛4銆
绛旓細(1)閲嶅姏鍔犻熷害g=10绫/绉²锛沇=FS =mgS =50x10x3 =1500(J)锛屻怞锛氱劍鑰炽(2)P=W/t =1500/10 =150(w)锛屻恮锛氱摝鐗广
绛旓細锛1锛塆 鐢 =m 鐢 g=50kg脳10N/kg=500N锛汫 涔 =m 涔 g=60kg脳10N/kg=600N锛涒埖G 鐢 锛淕 涔 锛宧 鐢 =h 涔 锛屽張鈭礧 鐢 =G 鐢 h 鐢 锛學 涔 =G 涔 h 涔 锛屸埓W 鐢 锛淲 涔 锛涳紙2锛塒 鐢 = W 鐢 t 鐢 = G 鐢 t 鐢 h 鐢 = 500N ...
绛旓細闈欐懇鎿﹀姏 閲嶅姏鍚戜笅 閭ｄ箞鎽╂摝鍔涘悜涓
绛旓細鈭电敳銆佷箼涓ゅ悓瀛︿粠鍚屼竴浣嶇疆鐖潌鍒椤剁锛屸埓鐖潌涓婂崌鐨勯珮搴鐩稿悓锛屽張鈭礧=Gh锛岀敳銆佷箼涓ゅ悓瀛︾殑浣撻噸G1锛欸2=5锛6锛屸埓鐢层佷箼涓鍚屽鐖潌鍋氬姛锛歐1锛歐2=G1h锛欸2h=G1锛欸2=5锛6锛屸埖鐢层佷箼涓ゅ悓瀛︾埇鏉嗘墍鐢ㄦ椂闂达細t1锛歵2=9s锛10s=9锛10锛屸埓鐢层佷箼涓ゅ悓瀛︾埇鏉嗗仛鍔熷姛鐜囷細P1P2锛漌1t1W2t2锛漌1W2脳t2...
