A jack is a device that uses force to lift heavy loads. The primary mechanism by which force is applied varies, depending on the specific type of jack, but is typically a screw thread or a hydraulic cylinder. Jacks may be categorized based on the type of mechanism used to generate the lifting force, typically mechanical power, hydraulic power, or pneumatic power. Mechanical jacks, such as the commonly used car jacks, lift heavy equipment and are rated based on the lifting capacity, which is typically expressed in terms of the number of tons that the jack can handle. Hydraulic jacks tend to have higher lifting capacities than mechanical jacks owing to the amount of force that can be generated by the hydraulic cylinders which product the lifting action. Common forms of hydraulic jacks include bottle jacks and floor jacks. Hydraulic jacks function based on a concept in fluid mechanics known as Pascal’s Principal. Essentially, if two cylinders (a large and a small one) are connected by an incompressible fluid, and a given amount of pressure is applied to one cylinder, that same pressure is imparted to the second cylinder through the fluid connecting them. However, because pressure i...