Differential pulley were. Next, the downward force acting on the lower pulley equal the upward forces acting on it, so Additionally, there is no net torque or moment around the compound pulley, so the clockwise torque is equal to the anticlockwise torque: Substituting "F" and "F" from the above equations, Rearranging gives As "F" = , Finally, the mechanical advantage, = or . Differential pulley A differential pulley, also called "Weston differential pulley", sometimes "chain hoist" or colloquially "chain fall", is used to manually lift very heavy objects like car engines. It is operated by pulling upon the slack section of a
Dump tackle Dump tackle The dump tackle is a tackling technique favoured mainly by rugby league players. The tackler wraps his arms around the ball carrier's thighs and lifts him a short distance in the air before forcibly driving him to the ground. The tackler must go to ground with the ball carrier for the tackle to be legal. In 2005 the IRB ruled that "the act of lifting an opponent off his feet in a tackle AND dropping or 'spearing' that player so that his head and/or upper body comes into contact with the ground first, is a dangerous tackle." therefore