'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 有用功、额外功和总功 1. 有用功(W有)指对人们有用的功。利用滑轮组的目的就是使物体...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 机械效率 1.定义:有用功跟总共的比值叫机械效率,用表示。=W有/W总。 2.特点:任何实...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 功的原理 人们使用机械有的是为了省力,有的是为了省距离,但省力必然费距离,省距...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 滑轮 滑轮是周边有槽,能绕着轴转动的小轮。 使用时,轴固定不动的滑轮叫做定滑轮。...
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'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})();...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})();...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 杠杆的平衡疑难点 ①在探究杠杆的平衡条件实验前,为什么要求调节杠杆使之在水平位置...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 用滑轮提升重物...
'); (window.slotbydup=window.slotbydup || []).push({ id: '8096091', container: s, size: '580,90', display: 'inlay-fix' });})(); 杠杆的特点及应用 难点聚焦:省力杠杆省了力却费了距离,使这种是省力。费力杠杆,虽...