The characteristics of Assur groups are（）
A. DOF=0
Basic link groups whose DOF=0 and cannot be further separated
C. Mechanical systems with lower pairs
D. Immobile mechanical systems with DOF=0
查看答案
According to the types of contact, kinematic pairs can be classified into lower pairs and higher pairs. A higher pair refers to（）
A. Kinematic pair with point contact
B. Kinematic pair with line contact
C. Kinematic pair with surface contact
D. Kinematic pair with body contact
What are the main features of machines（）
Assembly of man-made components
B. Determinate relative motions among different components
Can conduct work/energy conversion
D. Well designed shapes and structures
What are the composition elements of mechanisms（）
A. Links
B. Kinematic pairs
C. Parts
D. Components
The instantaneous center of velocity of two links that form a sliding pair is located at（）
A. Infinity point perpendicular to the direction of the guide line of the sliding pair
B. On the line perpendicular to the direction of the guide line of the sliding pair
C. In the middle of the guide line
D. At the contact point of the two links
微信支付 
支付宝支付