题目内容（请给出正确答案）

[主观题]

Which statement is correct for a moving point？

A、If at º 0 and an ¹ 0, then the point moves along a curve with varying speed.

B、If at = constant and an ¹ 0, then the point moves along a curve with uniformly varying speed.

C、If at ¹ 0 and an º 0, then the point moves along a curve with varying speed.

D、If at ¹ 0 and an º 0, then the point moves along a straight line with constant speed.

提问人：网友wyz840204 发布时间：2022-01-07

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第1题

If a rigid body undergoes translation, then the motion path of a point on the rigid body

A、must be a straight line.

B、must be a planar curve.

C、cannot be a spatial curve.

D、could be a spatial curve.

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第2题

If a rigid body is rotating around a fixed axis, then

A、at some instant, the accelerations of all points on a line perpendicular to the axis of rotation are not parallel to each other.

B、at some instant, the velocity magnitudes of any two points are proportional to their vertical distances to the axis of rotation.

C、at some instant, the velocities of any two points are parallel to each other.

D、it is impossible that the motion paths of all points are circular arcs.

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第3题

The three bars O1A, O2B and AB are pin-connected in one plane. At the position shown, O1A//O2B. In which case bar AB undergoes translation when bars O1A and O2B rotate in the plane.

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第4题

The velocities of two arbitrary points A and B on a rigid body are vA and vB, respectively. Which statement is correct?

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B、If ½vA½=½vB½ is satisfied, then the rigid body must be in translation.

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第5题

A right-angle bar is rotating around a fixed axis. The directions of the angular velocity ω and angular acceleration α are shown in the figures. Which one gives the correct directions for velocity, normal and tangential components of acceleration of point B?

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第6题

In the velocity parallelogram drawn based on the theorem of composition of velocities,

A、the absolute velocity is diagonal of the parallelogram formed by the transport velocity and relative velocity.

B、the transport velocity is diagonal of the parallelogram formed by the absolute velocity and relative velocity.

C、the relative velocity is diagonal of the parallelogram formed by the transport velocity and absolute velocity.

D、the algebraic sum of the projections of the absolute velocity, transport velocity and relative velocity on any axis is equal to zero.

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第7题

The disks are rotating around axes passing through point O. The accelerations of point M on the disks are shown. Which set of equations are correct?

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第8题

In the mechanism, the disk rotates with angular velocity w in counterclockwise direction. Which velocity parallelogram is correct if point A on bar AB is chosen as the moving point and the moving reference frame is attached to the disk?

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第9题

In the mechanism, bar OA rotates with angular velocity w in counterclockwise direction. Which velocity parallelogram is correct if point B on bar BCD is chosen as the moving point and the moving reference frame is attached to bar OA?

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