The mechanism shown in the figure below rotates about the vertical axis. The collar has massm=2.9 kg. The spring has an unstretched length of 660 mm and the spring constant isk=150 N/m. The distance d=420 mm , and the collar is required to stay a fixed distancer=1440 mm from the vertical axis.

a) If there is no friction between shaft AB and the collar, what angular velocity θ must the mechanism have to keep the collar at r=900 mm from the vertical axis?

b) Consider the same mechanism again, with m=2.9 kg, d=420 mm, k=150 N/m, only now, instead of being smooth, the collar and shaft have a maximum coefficient of friction of ?s=1.35.What is the minimum angular velocity required to keep the collar at a constant distance r=1440 mmfrom the axis of rotation?

Transcribed Image Text:

r - ア d r - ア d

Answer rating: 100% (QA)

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