23MM  price 5.4 yuan   60PCS/CTN

rivet tail with high-grade plastic handle single plus 1 yuan

&lt angle, also can be a wedge, its function is to pull out a nail. There is also a round nail.



when using leverage, in order to save energy, is should be with the power arm than a resistance arm long lever; if you want to distance from the provincial, it should be with a power arm is shorter than a resistance arm of the lever. Therefore, the use of leverage can save energy, but also the provincial distance. However, in order to save energy, it is necessary to move the distance; to want to move away from the distance, it must be a lot of money. It is impossible to realize that it is not possible to move a distance. On the basis of the "center of gravity" theory, Archimedes discovered the lever principle, that is, the distance between the distance and the weight of the fulcrum is inversely proportional to the weight of the two weights.
lever fulcrum of the not must meet the following three points system in the middle, basically is the lever fulcrum and point of application of force, force point.
wrote: the formula x = x dynamic power arm drag resistance arm, F1 * l1=F2 * L2 is a lever.
? Arm of force extension lever of
lever labor saving lever with laborious, both but different functions. For example a with a foot pump, or by hand pressure juicer is laborsaving lever (ARM & gt; force distance); but we must pressure larger distance, force end only less action. There is also an effort to leverage. For example the roadside crane, fishing hook at the tip of the rod, the end is the fulcrum, the middle is a hydraulic machine (torque & gt; arm), which is laborious leverage but laborious return is the middle point of application as long as the distance is small, the tip of the hanging hook will move considerable distances.
two levers are useless, just a place to go to labor or assessment, range of motion. There is another kind of thing called wheel axle, also can be used as a kind of leverage, but the performance is still possible sometimes to add the calculation of rotation.
ancient Greek scientist Archimedes has such a sentence handed down through the ages saying: "if you give me a fulcrum, can pry up earth" this sentence is not only inspiring motto, but also has a strict scientific basis.