一辆电动自行车(如图)的铭牌上给出了如下的技术参数表. 规格 后轮驱动直流永磁轻电机 车型 2
\u4e00\u8f86\u7535\u52a8\u81ea\u884c\u8f66\uff08\u5982\u56fe\uff09\u7684\u94ed\u724c\u4e0a\u7ed9\u51fa\u4e86\u5982\u4e0b\u7684\u6280\u672f\u53c2\u6570\u8868\uff0e \u89c4\u683c \u540e\u8f6e\u9a71\u52a8\u76f4\u6d41\u6c38\u78c1\u8f7b\u7535\u673a \u8f66\uff081\uff09\u7535\u52a8\u673a\u5728\u989d\u5b9a\u7535\u538b\u4e0b\u6b63\u5e38\u5de5\u4f5c\u65f6\u6d88\u8017\u7684\u7535\u529f\u7387\u4e3a\uff1aP\u5165=UI=40\u00d74W=160W\uff0c\uff082\uff09\u6839\u636e\u80fd\u91cf\u5b88\u6052\u5b9a\u5f8b\uff0c\u6709\uff1aP\u5165=P\u70ed+P\u51fa \u5373\uff1aUI=I2r+120 \u4ee3\u5165\u6570\u636e\uff0c\u6709\uff1a40\u00d74=42\u00d7r+120\u89e3\u5f97\uff1ar=2.5\u03a9\u7535\u52a8\u673a\u6b63\u5e38\u5de5\u4f5c\u65f6\u7684\u6548\u7387\uff1a\u03b7=P\u51faP\u5165\u00d7100%=120160\u00d7100%=75%\uff083\uff09\u81ea\u884c\u8f66\u963b\u529b\uff1af=0.02mg=0.02\u00d7\uff0830+70\uff09\u00d710=20N\u5300\u901f\u884c\u9a76\uff0c\u7275\u5f15\u529b\u4e0e\u963b\u529b\u5e73\u8861\uff0c\u4e3a\uff1aF\u7275=f=20N\u6545\u8f93\u51fa\u529f\u7387\u4e3a\uff1aP\u51fa=F\u7275v=fv\u89e3\u5f97\uff1av=P\u51faf=12020=6m/s\u7b54\uff1a\uff081\uff09\u6b64\u8f66\u7684\u7535\u52a8\u673a\u5728\u989d\u5b9a\u7535\u538b\u4e0b\u6b63\u5e38\u5de5\u4f5c\u65f6\uff0c\u6d88\u8017\u7684\u7535\u529f\u7387\u662f160W\uff1b\uff082\uff09\u6b64\u7535\u52a8\u673a\u7684\u5185\u963b\u662f2.5\u03a9\uff1b\u7535\u52a8\u673a\u6b63\u5e38\u5de5\u4f5c\u65f6\u7684\u6548\u7387\u4e3a75%\uff1b\uff083\uff09\u6b64\u4eba\u9a91\u8f66\u884c\u9a76\u7684\u6700\u5927\u901f\u5ea6\u4e3a6m/s\uff0e
\uff081\uff09\u7535\u52a8\u673a\u5728\u989d\u5b9a\u7535\u538b\u4e0b\u6b63\u5e38\u5de5\u4f5c\u65f6\u6d88\u8017\u7684\u7535\u529f\u7387\u4e3a\uff1aP=UI=40\u00d73.5W=140W\uff0e\uff082\uff09\u7535\u52a8\u8f66\u6d88\u8017\u7684\u7535\u529f\u7387\u4e00\u90e8\u5206\u4e3a\u673a\u68b0\u529f\u7387\uff0c\u53e6\u4e00\u90e8\u5206\u4e3a\u70ed\u529f\u7387\uff0c\u800c\u673a\u68b0\u529f\u7387\u548c\u70ed\u529f\u7387\u4e4b\u548c\u4e3a\u7535\u529f\u7387\uff0c\u6240\u4ee5\u8868\u4e2d\u53f3\u680f\u4e2d\u7684\u201c\u989d\u5b9a\u8f93\u51fa\u529f\u7387\u201d\u4e0e\uff081\uff09\u4e2d\u6240\u8ba1\u7b97\u7535\u529f\u7387\u4e0d\u76f8\u7b49\uff1b\uff083\uff09\u5f53\u7275\u5f15\u529b\u7b49\u4e8e\u963b\u529b\u65f6\uff0c\u901f\u5ea6\u6700\u5927\uff0c\u963b\u529b\u7684\u5927\u5c0f\u4e3a\uff1af=0.02G=0.02\u00d7\uff0860+30\uff09\u00d710=18N\uff0e\u6839\u636e\uff1aP\u51fa=Fv\uff0c\u53c8F=f\u89e3\u5f97\u6700\u5927\u901f\u5ea6\u4e3a\uff1av=P\u51faf\uff1d12018\uff1d6.67m/s\uff0e\u7b54\uff1a\uff081\uff09\u6b64\u8f66\u7684\u7535\u52a8\u673a\u5728\u989d\u5b9a\u7535\u538b\u4e0b\u6b63\u5e38\u5de5\u4f5c\u65f6\u6d88\u8017\u7684\u7535\u529f\u7387\u662f140W\uff1b\uff082\uff09\u6d88\u8017\u7684\u7535\u529f\u7387\u4e00\u90e8\u5206\u4e3a\u673a\u68b0\u529f\u7387\uff0c\u53e6\u4e00\u90e8\u5206\u4e3a\u70ed\u529f\u7387\uff0c\u673a\u68b0\u529f\u7387\u548c\u70ed\u529f\u7387\u4e4b\u548c\u4e3a\u7535\u529f\u7387\uff0e\uff083\uff09\u6b64\u4eba\u9a91\u8f66\u884c\u9a76\u7684\u6700\u5927\u901f\u5ea6\u4e3a6.67m/s\uff0e
(1)电动机在额定电压下正常工作时消耗的电功率为: P 入 =UI=40×4W=160W, (2)根据能量守恒定律,有: P 入 =P 热 +P 出 即:UI=I 2 r+120 代入数据,有: 40×4=4 2 ×r+120 解得:r=2.5Ω 电动机正常工作时的效率: η=
(3)自行车阻力: f=0.02mg=0.02×(30+70)×10=20N 匀速行驶,牵引力与阻力平衡,为: F 牵 =f=20N 故输出功率为: P 出 =F 牵 v=fv 解得: v=
答:(1)此车的电动机在额定电压下正常工作时,消耗的电功率是160W; (2)此电动机的内阻是2.5Ω;电动机正常工作时的效率为75%; (3)此人骑车行驶的最大速度为6m/s. |
绛旓細锛2锛夋牴鎹兘閲忓畧鎭掑畾寰嬶紝鏈夛細P 鍏 =P 鐑 +P 鍑 鍗筹細UI=I 2 r+120 浠e叆鏁版嵁锛屾湁锛40脳4=4 2 脳r+120瑙e緱锛歳=2.5惟鐢靛姩鏈烘甯稿伐浣滄椂鐨勬晥鐜囷細畏= P 鍑 P 鍏 脳100%= 120 160 脳100%=75%锛3锛夎嚜琛岃溅闃诲姏锛歠=0.02mg=0.02脳锛30+70锛壝10=20N鍖閫熻椹...
绛旓細锛1锛 锛2锛 锛3锛 璇曢鍒嗘瀽锛氾紙1锛夊洜涓 锛屾墍浠ユ湁 锛岃В寰 锛1鍒嗭級锛2锛変粠鍥句腑鍙緱 , 鏍规嵁鍏紡 锛2鍒嗭級锛3锛夊彈鍒扮殑闃诲姏锛 锛1鍒嗭級 鍙堢煡閬 褰撳叾鍖閫熻繍鍔ㄦ椂鏈夛細 鑱旂珛鍙緱锛 锛1鍒嗭級
绛旓細鐢靛姩鑷杞鐨勭數鍘嬫椂40V锛岀數娴佺殑澶у皬鏄3.5A锛屾墍浠ヨ緭鍏ョ殑鍔熺巼P=UI=40脳3.5W=140W锛屾墍浠姝g‘锛庢晠閫塁锛
绛旓細鐢辫〃鏍艰鍑虹數鏈虹殑棰濆畾鐢靛帇U=40V锛岄瀹氱數娴両=4A锛岄瀹氳緭鍑哄姛鐜嘝鍑=120W锛庯紙1锛夌數鏈鸿緭鍏ョ殑鏄數鍔熺巼锛屾诲姛鐜囩瓑浜庣數鍔熺巼锛屽緱鍒癙鎬=IU=40脳4W=160W 鏍规嵁鑳介噺瀹堟亽寰楋紝鍐呴儴鍙戠儹鍔熺巼P鐑=P鎬-P鍑猴紝鍙圥鐑=I2r鍒欐湁P鎬-P鍑=I2r r=160?12016=2.5惟锛2锛夌數鏈烘甯稿伐浣滄椂鐨勬晥鐜囄=P鍑篜鎬=12...
绛旓細鐢辫〃鏍艰鍑虹數鏈虹殑棰濆畾鐢靛帇U=40V锛岄瀹氱數娴両=3.5A锛岄瀹氳緭鍑哄姛鐜嘝 鍑 =120W锛屽嵆涓鐢靛姩鏈哄湪棰濆畾鐢靛帇涓嬫甯稿伐浣滄椂鐨勬満姊板姛鐜囷紝鎵浠閿欒锛涚數鏈烘甯稿伐浣滄椂娑堣楃殑鐢靛姛鐜囨诲姛鐜囦负 P 鎬 =IU=40脳3.5W=140W锛屾墍浠閿欒锛孊姝g‘锛涙晠閫塀锛
绛旓細M+m锛塧 鈶﹁В寰梐=0.4m/s 2 鈶х瓟锛氾紙1锛夌數鍔ㄨ嚜琛岃溅鐨鐢靛姩鏈哄湪棰濆畾鐢靛帇涓嬫甯稿伐浣滄椂鐨勬晥鐜囦负85.7%锛庯紙2锛変粎鍦ㄧ數鍔ㄦ満浠ラ瀹氬姛鐜囨彁渚涘姩鍔涚殑鎯呭喌涓嬶紝浜洪獞杞﹁椹剁殑鏈澶ч熺巼涓6.0m/s锛庯紙3锛夊綋杞﹂焩=2.0m/s鏃讹紝浜洪獞杞︾殑鍔犻熷害澶у皬涓篴=0.4m/s 2 锛
绛旓細h锛屽浘涔欑數鑳借〃绀烘暟鏄1362.6kW?h锛30min=0.5h钃勭數姹犳秷鑰楃殑鐢佃兘涓篧1=1362.6kW?h-1362.5kW?h=0.1kW?h锛涜搫鐢垫睜涓娆″厖婊$數鑰楃數閲廤2=0.5kW?h鈭磋搫鐢垫睜鐨勫厖鐢垫椂闂磘=W2W1脳0.5h=0.5kW?h0.1kW?h脳0.5h=2.5h锛涳紙3锛夌數鍔ㄨ嚜琛岃溅鍏嬫湇闃诲姏鎵鍋氱殑鍔焀=0.36kW?h=1.296脳106J锛孎=f=30N锛...
绛旓細浠庤〃鏍兼暟鎹腑璇诲嚭棰濆畾鐢靛帇涓40V锛岄瀹氱數娴佷负3锛5A锛涙晠棰濆畾鍔熺巼涓猴細P=UI=40脳3.5=140W锛涙晠閫塀锛
绛旓細锛1锛夌數鍔ㄨ嚜琛岃溅鐨杈撳嚭鍔熺巼涓篜 鍑 =180W锛涘綋杞︿互鏈澶ч熷害鍖閫熻繍鍔ㄦ椂锛岀壍寮曞姏绛変簬闃诲姏锛屾湁 鐗靛紩鍔汧=f=0.03mg=0.02脳锛30+70锛壝10=30N鐢盤 鍑 =Fv m 瑙e緱v m = P 鍑 F = 180 30 m/s=6m/s锛2锛夊綋杞﹂熶负v 1 =3m/s鏃讹紝鏍规嵁鐗涢】绗簩瀹氬緥锛屾湁 P 鍑 ...
绛旓細鏈夛細F-f=锛圡+m锛塧瑙e緱锛欶=f+锛圡+m锛塧=100Nv=PF锛100100=1m/s鏁呭姞閫熸椂闂达細t锛漹a锛10.8锛1.25s绛旓細锛1锛夋杞︽案纾佷綋鐢垫満鍦ㄩ瀹氱數鍘嬩笅姝e父宸ヤ綔鐨勬晥鐜囦负83.3%锛庯紙2锛変粎鍦ㄦ案纾佷綋鐢垫満浠ラ瀹氬姛鐜囨彁渚涘姩鍔涚殑鎯呭喌涓嬶紝浜洪獞杞﹁椹剁殑鏈澶ч熷害涓5m/s锛庯紙3锛変汉楠戣溅鍋氬寑鍔犻熻繍鍔ㄧ殑鏃堕棿涓1.25s锛