8. A rigid body rotates at 300 revolutions per minute around an axis which goes through the origin and points into the first octant, making an angle of $60^{\circ}$ with both the x- and y-axis. The velocity of a point $\vec{r} = (0,0,2)\mathrm{cm}$ is
(A)$\vec{v} = (0,0,600)\mathrm{cm/s}$
(B)$\vec{v} = (0,19.7,14.8)\mathrm{cm/s}$
(C)$\vec{v} = (-31.4,31.4,0)\mathrm{cm/s}$
(D)$\vec{v} = (31.4,31.4,0)\mathrm{cm/s}$
(E)$\vec{v} = (31.4,-31.4,0)\mathrm{cm/s}$
答案:登入後查看
統計: 尚無統計資料
統計: 尚無統計資料