Решение:
![image](https://tex.z-dn.net/?f=L%3Dv_%7B0%7Dt%5C%5C+%C2%A0%0AH%3D%5Cfrac%7Bgt%5E%7B2%7D%7D%7B2%7D%5C%5C+%3C%2Fp%3E%3Cp%3Et%5E%7B2%7D%3D%5Cfrac%7B2H%7D%7Bg%7D%5C%5C+%C2%A0%0At%3D%5Csqrt%5B2%5D%7B%5Cfrac%7B2H%7D%7Bg%7D%7D%3D%5Csqrt%5B2%5D%7B%5Cfrac%7B2%2A20%7D%7B10%7D%7D%3D2%5C%5C+%C2%A0%0AL%3Dv_%7B0%7Dt%5C%5C+%C2%A0%0Av_%7B0%7D%3D%5Cfrac%7BL%7D%7Bt%7D%3D5)
t^{2}=\frac{2H}{g}\\
t=\sqrt[2]{\frac{2H}{g}}=\sqrt[2]{\frac{2*20}{10}}=2\\
L=v_{0}t\\
v_{0}=\frac{L}{t}=5" alt="L=v_{0}t\\
H=\frac{gt^{2}}{2}\\
t^{2}=\frac{2H}{g}\\
t=\sqrt[2]{\frac{2H}{g}}=\sqrt[2]{\frac{2*20}{10}}=2\\
L=v_{0}t\\
v_{0}=\frac{L}{t}=5" align="absmiddle" class="latex-formula">