【单选题】下列工件定位面与定位元件不是限制三个自由度的是:( ACE )
【简答题】3-2Translation: Newton’s second law implies that: When a body is acted upon by a constant force, its resulting acceleration is inversely proportional to the mass of the body and is directly proportion...
【单选题】An artificial Earth satellite in an elliptical orbit has its greatest centripetal acceleration when it is at what location?
B.
farthest from the Earth
C.
between Earth and Moon
【判断题】When a body oscillating on a horizontal spring passes through its equiibrium position, its acceleration is zero. When the bob of an oscillationg simple pendulum passes through its equilibrium position...
【单选题】The magnitude of the normal acceleration is
A.
proportional to radius of curvature.
B.
inversely proportional to radius of curvature.
D.
zero when velocity is constant.
【单选题】Starting at time t = 0, an object moves along a straight line. Its coordinate in meters is given by x ( t ) = 75 t – 1.0 t 3 , where t is in seconds. When it momentarily stops its acceleration is:
【单选题】下列哪项不是工件以平面定位时所用的定位元件。( )。
【单选题】When acceleration is _______, a velocity of a particle is constant.
【单选题】以下不是平面定位元件的是:______。