????:1????????:????300?2??

2?????vx

3????????

4??????v??

5??????????

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

???????? ?“????????????????”

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

??1.55?? ????

???? 1/5

6??????????????18????????????,????????15?????,????????????83.94?,?1.44???????????,??????????????????????:???????19??3?????????????????

???:???

? ?