物理力学题，急求答案
\u7269\u7406\u529b\u5b66\u9898\uff0c\u6025\u6c42\u7b54\u6848\uff01\uff01v^2\u8868\u793av\u76842\u6b21\u65b9
\u6839\u636e\u52a8\u80fd\u5b9a\u7406\uff0cmgh=mv^2/2\uff0ch\u662f\u4e0b\u843d\u9ad8\u5ea6\uff0c\u6839\u636e\u51e0\u4f55\u5173\u7cfbh=R+r-(R+r)sinA\uff0c\u5f97v^2=2g(R+r)(1-sinA)
\u5c0f\u7403\u6240\u53d7\u5f39\u529bN=mgsinA\uff0c\u5f53\u5f39\u529b\u4e0d\u8db3\u4ee5\u652f\u6301\u5c0f\u7403\u7684\u79bb\u5fc3\u529b\u65f6\u4f1a\u8131\u79bb\u534a\u5706\uff0c\u6b63\u8981\u8131\u79bb\u65f6
mgsinA=mv^2/(r+R)
\u628av^2\u4ee3\u5165\u89e3\u5f97
sinA=2/3
A=arcsin(2/3)
\u4e00\u79cd\u5f88\u590d\u6742\u7684\u65b9\u6cd5\uff0c\u53ef\u4ee5\u770b\u770b
\u82e5g=10\uff0c\u5219\u6469\u64e6\u529bf=umg=6N
\u52a0\u901f\u5ea6a1=\uff0815-6\uff09/3=3,\u6c34\u5e73\u5411\u53f3
a2=\uff0812+6\uff09/3=6,\u6c34\u5e73\u5411\u5de6
a3=\uff0812-6\uff09/3=2\uff08\u5411\u53f3\u884c\u8fdb\u65f6\uff09\uff0ca3=\uff0812+6\uff09/3=6\uff08\u5411\u5de6\u884c\u8fdb\u65f6\uff09
\u5219 v1=a1*t1=3*6=18m/s,\u6c34\u5e73\u5411\u53f3\uff0c\u4f4d\u79fbs1=1/2*a1*t1*t1=54m
(1)\u7531\u4e8e\u6b64\u65f6\u901f\u5ea6\u5df2\u7ecf\u5230\u8fbe18m/s,\u5982\u679c\u53d1\u751f\u53d8\u5411\uff0c\u5219\u81f3\u5c11\u9700\u8981\uff1a
v1-a2*t2 =0 \u537318=6t2 =>t2=3s
v\u672b=a3*t3 \u5373 18=2t3 =>t3=9s \uff08\u7531\u4e8e\u4e34\u754c\u53d8\u5411\uff0c\u5728\u6b64\u60c5\u51b5\u4e0b\uff0c\u52a0\u901f\u5ea6a3\u987b\u75282\uff09
\u5373\u603b\u5171\u65f6\u95f4\u662f 6+3+9=18s\uff0c\u4e0d\u7b26\u5408\u9898\u610f\uff0c\u820d\u53bb\u8fd9\u79cd\u60c5\u51b5
\uff082\uff09\u73b0\u5728\u786e\u5b9a\u60c5\u51b5\u662fF2\u5e76\u672a\u4f7f\u7269\u4f53\u53d8\u5411\u8fd0\u52a8\uff0c\u5219\u53ef\u77e5\uff1a
v1-a2*t2+a3*(8-t2)=v\u672b \u537318-6t2+2(8-t2)=18 =>t2=2s \u5219t3=6s v2=6m/s
\u90a3\u4e48s=s1+s2+s3=54+(18*2-1/2*6*2^2)+(6*6+1/2*2*6^2)=150m
f=F1=20N
当拉力为F2=15N时，因仍向右运动，所以f仍向左
合外力F=f-F2=20-15=5N,方向向左
绛旓細f=F1=20N 褰撴媺鍔涗负F2=15N鏃讹紝鍥犱粛鍚戝彸杩愬姩锛屾墍浠浠嶅悜宸 鍚堝鍔汧=f-F2=20-15=5N,鏂瑰悜鍚戝乏
绛旓細鎵浠ヤ袱娈电殑鎬婚暱涓猴細L'=2L1=L0-mg/2k.鍙锛歀<L'
绛旓細1. 锛1锛夐噸鍔涗笉鍋氬姛锛屽洜涓轰笂鍗囩殑鏃跺欓噸鍔涘仛璐熷姛锛屼笅闄嶆椂鍋氭鍔燂紝浜岃呯浉绛夛紝姝ｅソ鎶垫秷銆傦紙2锛夌┖闃诲缁堝灏忕悆鍋氳礋鍔燂紝W = Fs = -2fh 2. (1) 鍥犱负鎷夊姏姘村钩锛屾墍浠ヨ搴=0锛 cosa = 1锛屽悓鏃朵笉鐢ㄨ冭檻閲嶅姏銆傛儏鍐典竴锛 鎷夊姏鍋氬姛锛歐 = 15*0.5 = 7.5J 鎯呭喌浜岋細 鎷夊姏鍋氬姛锛歐 = 15*0.5 = ...
绛旓細1 鍔ㄦ粦杞彈鍥涗釜鍔涳細涓ゆ牴缁冲瓙鐨勪袱涓媺鍔涳紙鐩哥瓑锛夈佺墿浣撶殑鎷夊姏锛堢瓑浜庣墿浣撶殑閲嶅姏锛夈佹粦杞殑閲嶅姏銆傚洓涓姏骞宠 锛屾墍浠2F=锛圙1+G2锛夎В寰楃怀瀛愭媺鍔汧=锛180+20锛/2=100N 2 缁冲ご鐨勭Щ鍔ㄩ熷害鏄墿浣撲笂鍗囬熷害鐨2鍊嶏紝V2=2*V1=2*0.1=0.2m/s P=FV=100*0.2=20w 3 鎻愬崌鐗╀綋鍋氱殑鍔熸槸鏈夌敤鍔燂紝...
绛旓細1.鐗╀綋鍦ㄦ枩闈笂杩愬姩鏃讹紝鍙楀埌閲嶅姏G銆佹敮鎸佸姏N銆佹懇鎿﹀姏f锛屽苟鍦ㄨ繖涓変釜鍔涗綔鐢ㄤ笅鍋氬寑閫熻繍鍔紝鍙楀姏骞宠 銆傚皢閲嶅姏G娌跨潃鏂滈潰鏂瑰悜鍜屽瀭鐩翠簬鏂滈潰鏂瑰悜鍒嗚В 娌挎枩闈㈡柟鍚戯細G*sin30掳=f 鍨傜洿浜庢枩闈㈡柟鍚戯細 G*cos30掳=N 鎽╂摝鍔沠=uN 鑱旂珛鍚庡彲寰 u=tan30掳=鏍瑰彿3/3 2.鐗╀綋鍦ㄥ钩闈笂杩愬姩鏃,鍙楀埌骞抽潰鐨勬敮鎸佸姏涓篘1=...
绛旓細鍗虫诲叡鏃堕棿鏄 6+3+9=18s锛屼笉绗﹀悎棰樻剰锛岃垗鍘昏繖绉嶆儏鍐 锛2锛夌幇鍦ㄧ‘瀹氭儏鍐垫槸F2骞舵湭浣跨墿浣撳彉鍚戣繍鍔紝鍒欏彲鐭ワ細v1-a2*t2+a3*(8-t2)=v鏈 鍗18-6t2+2(8-t2)=18 =>t2=2s 鍒檛3=6s v2=6m/s 閭ｄ箞s=s1+s2+s3=54+(18*2-1/2*6*2^2)+(6*6+1/2*2*6^2)=150m ...
绛旓細鐗╀綋閲嶅績鏈澶у彲浠ヤ笂鍗囧埌鐨勮窛绂伙紳闀挎柟褰㈢殑瀵硅绾跨殑涓鍗婏紳鈭(a²锛4a²)/2锛漚鈭5/2 鈭存鏃堕渶鍋氬姛W1锛滸a(鈭5-1)/2 鈶＄墿浣撶珫鐩存斁缃椂锛岀墿浣撻噸蹇冭窛绂诲湴闈㈣窛绂伙紳a 鍐嶆鎺ㄥ掔墿浣撴椂锛岀墿浣撻噸蹇冩渶澶у彲浠ヤ笂鍗囧埌鐨勮窛绂伙紳闀挎柟褰㈢殑瀵硅绾跨殑涓鍗婏紳鈭(a²锛4a²)/2锛漚鈭5/2 鈭存鏃...
绛旓細鍥炵瓟锛(1)鍙椾笁涓姏,涓涓噸鍔涘悜涓,涓や釜鎽╂摝鍔涘悜涓婁笖鐩哥瓑鍥犱负杩欎袱涓懇鎿﹀姏鏄竴瀵逛綔鐢ㄥ姏涓庡弽浣滅敤鍔,G=30N,2f=G.鎵浠=15N,(闈欐懇鎿︿笉鑳界敤f=ug,杩欐槸姹傚姩鎽╂摝鍔涚殑鍏紡) (2)鍖閫熶笂鍗,绔栫洿鏂瑰悜鐨勯噷鏄竴瀵瑰钩琛″姏,鎵浠ユ媺鍔涚瓑浜庨噸鍔涙槸30 N,
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绛旓細鐢ㄥ脊绨хГ娴嬪緱鐗╀綋鍦ㄧ┖姘斾腑鐨勯噸鍔涗负G锛岀劧鍚庢妸瀹冨叏閮ㄦ蹈鍏ュ瘑搴︿负蟻0鐨勬恫浣撲腑锛屾祴鍑虹墿浣撳湪娑蹭綋涓殑閲嶅姏涓篏鈥欙紝姹傦細(1)姝ょ墿浣撶殑浣撶НV锛(2)姝ょ墿浣撶殑瀵嗗害蟻1銆绛旀锛氫竴銆侀夋嫨棰 1-5 DACBA 6-10 BBACA 浜屻佸～绌洪 1銆佸皬浜 涔 2銆佸彉澶 涓嶅彉 3銆佸ぇ浜 绛変簬 4銆佺瓑浜 澧炲姞 5銆0.2N 涓嬫矇 ...
