In this situation the motives of the defendant and the reasonableness of their conduct are the factors used to determine the unreasonableness of their actions. This is one of the few exceptions to the rule that malice is not relevant in tort law. In Christie v Davey, the defendant was deliberately creating a noise to frustrate the claimants; based on this, it was held that their actions were malicious, unreasonable, and amounted to a nuisance.
A fixed pulley has a mechanical advantage of one, however, it is able to change the direction of force on an object. A movable pulley has a mechanical advantage of two and is connected to the object being moved.A block and tackle pulley provides a mechanical advantage of three and is made up of fixed and movable pulleys. Calculating the mechanical advantage of a pulley:ith a pulley, the user pulls one end of the rope and the other end of the rope pulls up on the object you want to move. The force produced by the user of the pulley is called the input force and the force pulling up on the object is called the output force.
The rope is threaded through the pulleys to provide mechanical advantage that amplifies that force applied to the rope. In order to determine the mechanical advantage of a block and tackle system consider the simple case of a gun tackle, which has a single mounted, or fixed, pulley and a single movable pulley. The rope is threaded around the fixed block and falls down to the moving block where it is threaded around the pulley and brought back up to be knotted to the fixed block.