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Theta=0 was defined as when the penguin was at its highest point and about to drop down. We can see that at this point, the position of the penguin is at 2.3 cm, or 3.9-1.6 cm, matching the maximum radius of the cam (radius of the larger semicircle) minus the minimum radius of the cam (radius of the smaller semicircle). During the drop, the point of the cam which is in contact with the base of the follower is the sharp corner of the snail cam. Thus, the vertical distance is the maximum radius of the cam, multiplied by the cosine of theta. A rest period of no motion follows, as the radius is at a constant minimum when the small semicircle of the cam points upwards. At theta=180, the cam radius begins to increase, following the simple harmonic motion mentioned in the previous section.
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