Mechanical advantage force applied at "A" the end of the rope, and let "F" be the force at "B" on the moving block. Like the velocities "F" is directed downwards and "F" is directed upwards. For an ideal block and tackle system there is no friction in the pulleys and no deflection or wear in the rope, which means the power input by the applied force "F""V" must equal the power out acting on the load "F""V", that is The ratio of the output force to the input force is the mechanical advantage of an ideal gun tackle system, This analysis generalizes
Fly system used for spot rigging, where they are often equipped with swivel-pivots to divert lines across a large range of angles. Tension blocks are single-sheave blocks located at the lower end of the arbor guide track, beneath the arbor. The operating line is reeved through the tension block from the bottom of the arbor through the rope lock. Tension blocks typically ride vertically along the arbor guide system tracks, instead of being fixed, to allow for variation in the length of the operating line. Counterweights are heavy objects that are used to balance the lineset loads in a fly system. In