Motion given by two point envelopes

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Specification of a motion

The following rules are valid for a motion given by point envelope (a) of straighl line a and point envelope (b)of straight line b

- Straight line a passes through point envelope (a) at each instant.

- Straight line b passes through point envelope (b at each instant.

- Angle ψ formed by straight lines a and b does not change.

This motion and the motion given by two linear trajectories are inverse motions.

Animation of a motion (motion given by two point envelopes)

Moving centrode (motion given by two point envelopes)

Trajectory of a point (motion given by two point envelopes)

Envelope of a circle (motion given by two point envelopes)

Envelope of a straight line (motion given by two point envelopes)

Specification of inverse motion (motion given by two point envelopes)

- Straight line a becomes the trajectory of point envelope (a)

- Straight line b becomes the trajectory of point envelope (b).

- The distance between moving points (a) and (b) does not change.

Moving centrode (motion given by two point envelopes)