15.6 : 영속도의 순간중심

Consider a wheel in general planar motion. The absolute velocity of point B is expressed as the vector sum of the absolute velocity of point A and the relative velocity of point B with respect to point A.

If point A is chosen such that it has a zero velocity at a given instant, then the velocity expression for point B gets simplified. Here, point A is called an instantaneous center of zero velocity or IC.

This point lies on an axis perpendicular to the plane of motion. The intersection of this axis with the plane defines the location of the instantaneous axis of rotation.

Here, point B appears to move momentarily in a circular path around the instantaneous center of zero velocity.

The velocities of different points on the wheel can be calculated using the velocity equations with the corresponding radial distances with respect to point A.

For a wheel undergoing general planar motion, the instantaneous center of zero velocity point is not fixed but changes with the motion of the wheel.