Bunch of Questions about Simple Machines?

Question

1.First of all, I want to know what system is used in Car Jack (lift).
Is it a penumatic system or hydraulic system? Please explain how it is used in making this machine work.
2. What is Car Jack (lift) supposed to do? What simple machines are in Car Jack (lift) and what part does this play in making the machine work?
3. What did they use this machine in past?

Please answer my questions. Thank You~

Answer 1

There are two basic types of lifts: hydraulic and purely mechanical. A cheap scissors jack in today's automobile uses a ramp in the form of an ACME (yes, not from the cartoons) screw and nut and a series of linkages to apply mechanical advantage (Archimede's lever) to the car. Force*Distance = work. You apply a small force over a long distance by repeatedly turning the screw. The car has a large force (weight) which experiences a small displacement from the jack.

The other type employs fluids and pumps to create the forces necessary to lift heavy objects. Again the same principal exists between hydraulic cylinders of different diameters. Pressure = Force / area. Pushing on a cylinder with a small diameter over a long distance can cause a cylinder with a large diameter to move a short distance with a lot of force. That's what a lift does.

In the old days, they used "block and tackle." These were pulley systems which allowed a rope to be pulled over a long distance and move the hook vertically a short distance under a heavy load. This was the most common way to amplify the human workforce and lift heavy objects.

Tell me if I get an "A" on the assignment.