Mechanical advantage device advantage for a screw can be calculated using the following equation: where Note that the actual mechanical advantage of a screw "system" is greater, as a screwdriver or other screw driving system has a mechanical advantage as well. Mechanical advantage device A simple machine that exhibits mechanical advantage is called a mechanical advantage device - e.g.: Consider lifting a weight with rope and pulleys. A rope looped through a pulley attached to a fixed spot, e.g. a barn roof rafter, and attached to the weight is called a "single pulley". It has a mechanical advantage (MA) = 1 (assuming frictionless
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