A plane figure moves in its plane. The velocity vectors of two different points on the plane figure are the same at a instant. Which statements are correct（）
All points in the plane figure have the same velocity at this instant
B. All points in the plane figure have the same acceleration at this instant
C. The angular acceleration of the plane figure must be zero, but the angular velocity may not be zero at this instant
D. The angular velocity of the plane figure must be zero, but the angular acceleration may not be zero at this instant
查看答案
Richard Brasher is to__（）
A. become chief executive
B. be on a shortlist
C. be a high-flier
D. work within Tesco
Which is NOT the reason why many human resource managers create a training calendar（）
A. Because employees need more professional skills
Because employees need to break the cycle of monotony at work
C. Because training may provide more opportunities for employees
D. Because routine work might demotivate employees
It seems that__（）
A. a lot of people left Boots
Boots is thriving quickly
C. Boots has decided to reform
D. some senior staff have left or will leave Boots
The velocities of two arbitrary points A and B on a rigid body are vA and vB, respectively. Which statement is correct（）
A. If the rigid body is in translation, then ½vA½=½vB½ must be satisfied
B. If ½vA½=½vB½ is satisfied, then the rigid body must be in translation
C. If the rigid body is in translation, then ½vA½=½vB½ must be satisfied and the directions of the two velocities could be different
D. If the rigid body is in translation, then the directions of vA and vB must be the same but probably |vA|¹|vB
微信支付 
支付宝支付