Which of the following has the surface constant choose all t
     Which of the following has the surface constant?  (choose all that applies)  Plane Pair  Gear Pair  Universal Pair  Helix Pair  Which of the following has the degrees of freedom of 3?  (choose all that applies)  Sphere Joint  Gear Pair  Prism Pair  Cam Pair 
  
  Solution
a) A - Plain Pair
D- Helix Pair
b) A - Sphere Joint
A spherical pair keeps two spherical centers together. Two rigid bodies connected by this constraint will be able to rotaterelatively around x, y and z axes, but there will be no relative translation along any of these axes. Therefore, a spherical pair removes three degrees of freedom in spatial mechanism. DOF = 3.

