Horizontal Component Vector and Changing Angles

To investigate the concept of a horizontal component vector and changing angles.

Definition and Theory
By changing the angle of the cable, the horizontal force in the compressive member changes. In a cable structure shown below, the load (P) on one end of the cable is the same as the reaction force (Pr) on the other. Force (P) can be broken into vertical (Pv) and horizontal (Ph) components. The vertical component (Pv) = (Pr) sine q and the horizontal component (Ph) = (Pr) cosine q. As the angle goes from 90� to 0� the force in the horizontal component (Ph) increases from 0 to (P).

  • Rh = Horizontal Reaction
  • Rv = Vertical Reaction
  • P = Load
  • Pr = Reaction Force
  • Ph = Horizontal Component
  • Pv = Vertical Component
  • q = Angle of Cable
  • SFh = Sum of Horizontal Forces
  • SFh = Ph - Rh = 0
  • Ph = Rh (the horizontal components are equal in this diagram)


Laboratory Worksheet