The building stands tall because of its strong pillars, and the screw jack lifts a thousand pounds of weight with great resilience, because its powerful strength comes from its own hard body and solid foundation. Therefore, we can say that the reason why a jack can lift a thousand tons of heavy objects is not only due to its own structural advantages, but also to external support.

The internal components of a screw jack that can generate force include transmission gears, lifting sleeves, and other parts, which gradually convert human labor into mechanical force and should not be underestimated.

The external support is mainly reflected in two aspects. One is the hard and solid ground. If we place a jack on a soft and muddy ground to lift heavy objects, the jack will be unable to exert its upward lifting force under the heavy pressure of the object, and will be vulnerable, retreating one after another, being continuously pressed down by the heavy object, and eventually burying itself or tipping over to the ground. The other is the force attached by the human hand to the jack handle, which is related to the lifting speed and frequency of the jack lifting sleeve.

The ability of a screw jack to lift a heavy object requires joint internal and external force, and this force also varies in magnitude. In summary, strong force produces efficiency, while small force grinds away foreign labor.