角量与线量的关系 de do d20 C三 dt dt ⑦=rt a=rae+roe三 角量与线量的关系 et r   v =    r  t e  v  2 n t   a r a r = = t a  n a  n 2 t a r e r e    =  +  dt d  = t t 2 2 d d d d   = = a 