Assertion: gear's body | /r/HasAspect | planar relative motion
Facets:
Source sentences:
text: The instantaneous center or instant center is defined in two ways (Bradford & Guillet 43): When two bodies have planar relative motion, the instant center is a point on one body about which the other rotates at the instant considered.
text: When two bodies have planar relative motion, the instant center is the point at which the bodies are relatively at rest at the instant considered.