Which tools are designed using the lever principle?

Wrench, pliers, screwdriver, jack, crowbar, etc. It is designed by using the lever principle.

Levers can be divided into labor-saving levers, labor-saving levers and equal-arm levers, and none of them can save both distance and labor.

1, labor-saving lever:

l 1 & gt； L2，f 1 & lt； F2, labor saving and distance consuming.

Such as claw hammer for nail pulling, straw cutter, bottle opener, hob, moving pulley, scissors for handcart cutting iron sheet, steel bar scissors, etc.

2, laborious lever:

l 1 & lt； L2，f 1 & gt； F2, laborious and distance-saving.

For example, fishing rods, tweezers, chopsticks, scissors for boaters and barbers.

3. Equal arm lever:

L 1=L2, F 1=F2, which is neither labor-saving nor laborious, and does not move much.

Such as scales and crown blocks.

Extended data

Archimedes has a long-standing famous saying: "Give me a fulcrum and I can pry up the whole earth!" " "This sentence means the principle of leverage.

Archimedes first regarded some empirical knowledge in the practical application of lever as "self-evident axioms", and then from these axioms, he used geometry and strict logical argumentation to get the principle of lever.

These axioms are:

(1) Hang equal weights at both ends of the weightless bar at the same distance from the fulcrum, and they will be balanced;

(2) Hang unequal weights at the same distance from the fulcrum at both ends of the weightless bar, and the heavy end will fall;

(3) Hang an equal weight at both ends of the weightless bar with different distances from the fulcrum, and the far end will incline downward;

(4) The function of one weight can be replaced by the function of several evenly distributed weights, as long as the position of the center of gravity remains unchanged. On the contrary, several evenly distributed weights can be replaced by a weight hanging from their center of gravity.

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