Engineering Statics


Two transmission belts pass over sheaves welded to an axle supported by bearings at B and D. The sheave at A has a radius of 2.5 inches, and the sheave at C has a radius of 2 inches. Knowing that the system rotates at a constant rate, determine the tension T and the reactions at B and D. Assume that the bearing at D oes not exert any axial thrust and neglect the weights of the sheaves and axle.

The rules of statics operate whenever an object is not 
accelerating.  Therefore, the fact that the system rotates 
at constant rate has no effect on the equations. Moments are 
taken about the line defined by the axis of the axle.
The tension T is found.
The force equation is written in the y direction.
The force equation is written in the z direction.
The moment equation is taken about the y axis drawn 
vertically through point B.