在 xoy 平面内充满了均匀介质, t =0 时刻坐标原点 O 处的质点开始沿 y 轴做运动,其位移时 p 间关系式为 y =10sin( ) cm ,它在介质中形成的横波只向 x 轴正方向传播,某时刻波恰好传到 x =6m 处,波形图象如图所示,已知 M 点的平衡位置在 x= m 处,则下列说法正确的是
【简答题】39) Suppose there are two countries that are identical in every way with the following exception: Country A has a higher saving rate than country B. Given this information, we know with certainty that...
【单选题】Passage 3It happens to every medical student sooner or later. You get a cough that persists for a while. Ordinarily, you would just ignore it—but now armed with your rapidly growing medical knowledge,...
A.
you cannot be a good medical student or a medical worker
B.
you are haunted by a possibly inexistent disease
C.
you will never get rid of this disease
D.
you are tortured by several diseases at the same time