【多选题】下面关于光滑圆柱铰链(固定铰)约束表述正确的是?
A.
限制被约束物体在垂直于销钉轴线的平面内任何方向的位移
C.
约束力作用在与销钉轴线垂直的平面内,并通过销钉中心,方向待定
【判断题】光滑面约束对物体的约束力作用在光滑面与物体的接触点处,沿接触面处的公法线,是指向被约束物体的压力。
【单选题】在加工阶段划分中,保证各主要表面达到图样所规定的技术要求的是( )。
【单选题】Suppose a small country experiences economic growth which leads to an increased willingness to trade. The country’s terms of trade will _____ because the prices of its exports will _____ relative to t...
B.
b. improve; not change
C.
c. remain unaffected; not change
D.
d. remain constant; fall
【单选题】Suppose a small country experiences economic growth which leads to an increased willingness to trade. The country’s terms of trade will _____ because the prices of its exports will _____ relative to t...
C.
remain unaffected; not change
【单选题】以下哪一种运输适合在陆地地表进行长距离的运输?
【单选题】解释酶能够识别一个假手性C上两个相同的基团的假说是
【简答题】Which country leads the world in research and developmentspending?A. United States B. Japan C. China D. Germany