u2sinαg\frac{\mathrm{u}^{2} \sin \alpha}{g}gu2sinα
u22g\frac{u^{2}}{2 g}2gu2
2usinα8\begin{array}{l}2 u \sin \alpha\\\text{8}\end{array}2usinα8
u2sin2αg\frac{u^{2} \sin ^{2} \alpha}{g}gu2sin2α