初三物理题（压强）！！！！！详细解题者，加分，谢谢！！！
\u521d\u4e09\u7269\u7406\u538b\u529b\u548c\u538b\u5f3a\u600e\u4e48\u7b97\u6c42\u8be6\u7ec6\u89e3\u7b54\u89e3\uff1a\u5bf9\u5730\u9762\u7684\u538b\u529bF=(G1+G2)=(m1+m2)g=(48kg+12kg)X10(N/kg)=600N
\u603b\u63a5\u89e6\u9762\u79ef\u4e3a40\u5e73\u65b9\u5398\u7c73\uff1d0.040m²
\u5bf9\u5730\u9762\u7684\u538b\u5f3aP=F/S=²N/0.040m²=15000Pa
\u5982\u679c\u7b49\u9ad8\u5219\u539f\u6765\u7684P\u7532=P\u4e59\u6240\u4ee5
\u8fd9\u662f\u4e2a\u4e0d\u7b49\u9ad8\u7684\u5706\u67f1\u4f53\uff01\uff01\uff01\u4e14\u9ad8\u5ea6\u7532<\u4e59\uff0c\u8fd9\u662f\u6761\u4ef6\uff0c\u662f\u5417\uff1f
\u6839\u636eP=Mg/S\u7684\u5b9a\u4e49\uff0c\u5f53S\u4e0d\u53d8\u65f6\uff0cP\u968fMg\u6210\u6b63\u6bd4\u4f8b\u53d8\u5316\uff0c\u7531\u4e8e\u662f\u5706\u67f1\u4f53\uff0c\u5219\u968f\u9ad8\u5ea6H\u6210\u6b63\u6bd4\u4f8b\u53d8\u5316\u3002
\u5219\u8bbe\u539f\u6765\u7532\u9ad8\u4e3aH\u7532\uff0c\u539f\u6765\u4e59\u9ad8\u4e3aH\u4e59\uff0c\u622a\u53bb\u7684\u76f8\u540c\u9ad8\u5ea6\u4e3ah\uff0c\u539f\u59cb\u5bf9\u5730\u538b\u5f3a\u5206\u522b\u4e3aP\u7532\u548cP\u4e59\uff0c\u76f8\u540c\u65f6\u7684\u538b\u5f3a\u4e3ap
p=P\u7532*\uff08H\u7532-h\uff09=P\u4e59*\uff08H\u4e59-h\uff09
\u7531\u4e8eH\u7532<H\u4e59\u5219\uff1a\uff08H\u7532-h\uff09<\uff08H\u4e59-h\uff09
\u6240\u4ee5P\u7532/P\u4e59>1,
\u539f\u6765\u5bf9\u6c34\u5e73\u5730\u9762\u7684\u538b\u5f3aP\u7532>P\u4e59
\u8fd9\u7c7b\u9898\u4e3b\u8981\u662f\u627e\u51fa\u538b\u5f3a\u4e0e\u538b\u5f3a\u4e4b\u95f4\u7684\u5173\u7cfb\uff0c\u8fd9\u91cc\u662f\u901a\u8fc7\u7ebf\u6027\u6bd4\u4f8b\u5173\u7cfb\u505a\u51fa\u6bd4\u8f83
G=F总-G木=600N-12N=588N
m=G÷g=588N÷9.8N/Kg=60Kg
答：中学生的质量为60千克
F人=G=588N S鞋=0.02m²×2=0.04m²
P人=F人÷S鞋=588N÷0.04m²=14700Pa
答他站立时对木板的压强为14700帕
(1)P=F/S
6000=F/0.1
F=600N
F人=600-12=588N
G=mg
m=588/9.8=60kg
(2)P=F/S
P=588/0.04
P=14700Pa
OK就是这样吧
绛旓細姘村鏉簳鐨鍘嬪己=pgh=1000*10*0.08=800Pa 50cm^2=0.005m^3 鎵浠ュ帇鍔=800*0.005=4N 鏉瓙瑁呬笂姘村悗鐨勬婚噸鍔=0.6*10=6N 60cm^2=0.006m^2 鍘嬪己=6/0.006=1000Pa
绛旓細鍘嬪姏涓庤川閲忔垚姝ｆ瘮锛屽嵆F=G=m*g 璁剧敳鍘嬪姏銆佸帇寮恒佹帴瑙﹂潰鍒嗗埆涓篎1銆丳1銆丼1锛屼箼鍘嬪姏銆佸帇寮哄垎鍒负F2銆丳2銆丼2 P1=F1/S1,P2=F2/S2,鍘熸潵鐨凱1=P2锛屽苟涓擲1<S2锛屾墍浠1<F2(缁撹1)褰撳姞100k鐮濈爜鍚庯紝绛夊紡鍙樹负(P12涓哄姞涓100k鍚庣敳鐨勫帇寮猴紝P22涓哄姞涓100K鍚庝箼鐨鍘嬪己)P12=(F1+100)/S1=F1/S1+100/S1=...
绛旓細锛1锛塰A=pA/蟻姘磄 =980甯/(1.0脳103鍗冨厠/绫3脳9.8鐗/鍗冨厠) =0.1绫 2鍒 璇存槑锛氬叕寮1鍒嗭紝浠ｅ叆鍜岀粨鏋滃叡1鍒嗐傦紙2锛塆鐢=蟻姘绰稸姘磄 =1.0´103鍗冨厠/绫3 脳0.01绫2脳锛0.1绫+0.3绫筹級脳9.8鐗/鍗冨厠 =39.2鐗 璇存槑锛氬叕寮1鍒嗭紝浠ｅ叆鍜岀粨鏋滃叡1鍒嗐侳= G鐢+ G瀹=39.2...
绛旓細P灏=F/S澶=G/S妗=60/(200脳10^-4)=3000Pa 鏍规嵁鍏紡P=F/S锛屾按骞虫闈㈠帇鍔=閲嶅姏锛岄噸鍔涗笉鍙樻椂锛屽彈鍔涢潰绉秺澶э紝鍘嬪己瓒婂皬锛屽綋灏忕殑搴曢潰绉100鍘樼背²鏀惧湪妗岄潰鏃讹紝鍙楀姏闈㈢Н涓100鍘樼背²褰300鍘樼背²鏀惧湪妗岄潰锛屽彈鍔涢潰绉负妗岄潰闈㈢Н200鍘樼背²...
绛旓細鐡跺姞鐩栧悗鎴愬瘑闂鍣紝鍒氬紑濮嬶紝鐡跺唴姘撮潰涓哄ぇ姘斿帇锛岄殢鐫A瀛斻丅瀛旂殑娉勬按锛屾按娣卞彉娴咃紝鐡跺唴涓婃柟鐨勭┖闂村澶э紝涓瀹氶噺鐨勬皵浣鍘嬪己灏变笅闄嶏紝杩欓兘浣垮緱A銆丅瀛旂殑鍘嬪己鍙樺皬锛屾祦鍑虹殑姘撮噺鍙樺皬锛屽皠璺濆彉鐭傜敱浜嶣鐐圭殑姘存繁姣擜鐐瑰ぇ锛屾墍浠鐐圭殑鍘嬪己澶т簬A鐐癸紝褰揂鐐圭殑鍘嬪己绛変簬澶ф皵鍘嬬殑閭ｄ釜鐬棿锛孉瀛斿氨涓嶅嚭姘达紝涔熶笉杩涙皵...
绛旓細鑰冪偣锛鍘嬪己鐨勫ぇ灏忓強鍏惰绠楋紱瀵嗗害鍏紡鐨勫簲鐢紱娑蹭綋鍘嬪己璁＄畻鍏紡鐨勫簲鐢紟涓撻锛氬帇寮恒佹恫浣撶殑鍘嬪己锛庡垎鏋愶細锛1锛夊埄鐢ㄥ叕寮徬= m V 鐨勫彉褰㈠彲鐩存帴姹傛按鐨勮川閲忥紱锛2锛堿瀹瑰櫒瀵规按骞虫闈㈢殑鍘嬪己灞炲浐浣撳帇寮猴紝鍏跺帇鍔涗负姘村拰瀹瑰櫒鐨勬婚噸鍔涳紝鍐嶅埄鐢ㄥ叕寮弍= F S 鏉ユ眰瀵规闈㈢殑鍘嬪己锛涳紙3锛夌煡閬撳鍣ㄧ殑搴曢潰绉互鍙婃按鍜岄厭绮剧殑...
绛旓細F鎬=P鎬籗鏈=6000Pa脳0.1m²=600N G=F鎬-G鏈=600N-12N=588N m=G梅g=588N梅9.8N/Kg=60Kg 绛旓細涓鐢熺殑璐ㄩ噺涓60鍗冨厠 F浜=G=588N S闉=0.02m²脳2=0.04m²P浜=F浜好稴闉=588N梅0.04m²=14700Pa 绛斾粬绔欑珛鏃跺鏈ㄦ澘鐨鍘嬪己涓14700甯 ...
绛旓細閫氳繃灏辨槸璧拌繃鍚楋紵閭ｄ箞锛欶=500N,S=125cm²=0.0125m²p=F/S=500N/0.0125m²=40000甯 p=40000PA,S=175cm²=0.0175m²鐢眕=F/S寰桭=pS=40000PA*0.0175m²=700N 700N-500N=200N 鍙互璐熼噸200N鐨勪笢瑗块氳繃鍐伴潰 ...
绛旓細閫塂 鍥惧簲璇ユ槸杩欎釜鍚э紵濡傚浘锛屼綘鐪嬫牴鎹=m/v锛岃繖閲岃川閲忎綋绉悓鏃跺噺鍗婏紝鎵浠ュ瘑搴︿笉鍙樸傚叧浜庡帇鐞冿紝鏍规嵁P=F/S锛屾帴瑙﹂潰绉病鍙橈紝浣嗘槸璐ㄩ噺灏忎簡涓鍗婏紝鍘嬪姏涔熷氨鍑忓皬浜嗕竴鍗婏紙鍥犱负杩欓噷鍘嬪姏绛変簬閲嶅姏锛屽彲浠ラ氳繃G=mg鍒ゆ柇锛岃繖閲屽帇鍔涘拰璐ㄩ噺鏄姣斿叧绯伙級鎵浠ユ帴瑙﹂潰绉笉鍙橈紝鍘嬪姏鍑忓皬锛屾墍浠鍘嬪己涔熷氨灏忎簡 甯屾湜瀵逛綘鏈夊府鍔 ...
绛旓細鍥犱负璇ュ悓瀛︿笉浼氳緭10鐨勬鏂规暟鎵浠ユ垜灏辨崲绉嶅啓娉曪細A锛氱殑璐ㄩ噺=瀵嗗害脳浣撶Н=8脳103鍗冨厠/绫3脳1.25脳10-4绫3 =1kg , A鐨勯噸鍔涗负9.8N,B 锛氬鍦伴潰鐨鍘嬪己pB锛歅=F/s=0.49鐗涢】/4脳10-4绫2=1225甯 锛3锛夊洜涓篈B鍧囦负姝ｆ柟浣撳彲鍏堟眰浠栦滑杈归暱 A鐨勮竟闀匡細a=0.05绫 B鐨勮竟闀:b=0.02 绫 ...
