There are various types of jacks that we can come into contact with in life, mainly including rack jacks, screw jacks, hydraulic jacks, and so on. Among these types of jacks, the screw jack is a simple force transmission process, which is actually not as labor-saving as the hydraulic jack.

The root of the labor-saving feature of hydraulic jacks lies in their Pascal lifting system. When a small force is applied to the jack from the outside, a certain amount of pressure is exerted on the piston in the hydraulic system, and the force is reflected on the other piston in increments of pressure.

Although the working principle is a bit complex, for hydraulic jacks, the larger the area ratio of the large piston to the small piston, the more labor-saving it is. However, when the area of the jack piston is smaller, the height it needs to rise or fall is greater, which invisibly increases the pressing time of the operator.

In addition, activities such as roller skating, inclined surfaces, levers, etc. are all labor-saving and effortless. Using them does not give you extra strength, to some extent they simply adopt a 'divide and conquer' strategy, allowing you to successfully perform work on seemingly impossible heavy objects.