# 斜面

## 機械利益

$\mathbf{r}_A = R (\cos\theta, \sin\theta)$

$\mathbf{v}_A = v_A(\cos\theta, \sin\theta).$

$P_{\mathrm{in}} = fv_A$

$P_{\mathrm{out}} = \mathbf{W}\cdot\mathbf{v}_A = (0, W)\cdot v_A(\cos\theta, \sin\theta) = Wv_A\sin\theta$

$MA= \frac{W}{f}= \frac{1}{\sin\theta}$

$\sin\theta = \frac{H}{L}$

$MA = \frac{W}{f} = \frac{L}{H}$

$MA = \frac{W}{F} = 5$

## 注释

1. ^

挈：兩輪為高，兩輪為輲，車成梯形也。重其前，弦其前，載弦其前，載弦其軲，而縣重於其前。是梯挈且挈則行。凡重，上弗挈，下弗收，旁弗劫，則下直杝，或害之也流。梯者不得流直也。今也廢尺於平地，重不下，無旁也。若夫繩之引軲也，是猶自舟中引橫也。

——《墨子·经说下》第二八条

## 參考文獻

1. ^ Anderson, William Ballantyne. Physics for Technical Students: Mechanics and Heat. New York, USA: McGraw Hill. 1914: 112–122.
2. ^ 2.0 2.1 Moon, Francis; Moon, F. C., The machines of Leonardo da Vinci and Franz Reuleaux:kinematics of machines from the Renaissance to the 20th century illustrated, annotated, Springer, pp. 28, 2007, ISBN 9781402055980
3. ^ Prater, Edward L. Basic Machines. Naval Education and Training Professional Development and Technology Center, NAVEDTRA 14037. 1994.
4. ^ Bureau of Naval Personnel. Basic Machines and How They Work. Dover Publications. 1971.
5. ^ Mays, L. Ancient Water Technologies illustrated. Springer. 2010: pp. 16. ISBN 9789048186310.
6. ^ 6.0 6.1 馬赫, 恩斯特, The science of mechanics; a critical and historical account of its development, Watchmaker Publishing, pp. 134–136, 140–141, 2010 [1919], ISBN 978-1603863254
7. ^ 吴毓江，墨子校注，北京：中华书局，1993年，第534页
8. ^ 墨子. 《經說下》. 中國哲學書電子化計劃.
9. ^ 9.0 9.1 Dugas, R., A History Of Mechanics, New York: Dover Publications, Inc., pp. 33–35, 124–126, 1988, ISBN 0-486-65632-2