?????????????,

UPVC????????

??????????????????

hw=hf+hj?3?

?????

????hw??????????m?
????hf??????????m?
????hj??????????m.

UPVC???????????????????

hf=?L/c2R?v2?4?

?????

????L???????m?
????c??????
????R?????????m.

??????????????

hj=??v2/2g??5?

?????

???????????????
????g???????9.81m/s2.

???????

?????0.014???0.012?upvc?0.009?RPR?0.0084????0.013?0.015