What is the correct name for the earth, sand, cart in the construction site?
In the lever balance, the power arm is several times the resistance arm, the power is a few parts of the resistance.
(1) determine the position of the lever pivot.(2) distinguish the power and resistance of the lever, make clear its size and direction, and give the schematic diagram of the output as much as possible.(3) determine the force arm of each force.(4) according to the lever balance condition, the relation formula is listed and solved.
A method of minimizing power(1) after finding the maximum power arm, the passing point is the vertical of the power arm;(2) according to the actual power, the lever can rotate in the opposite direction of the resistance, thus determining the direction of power.
Method of finding the maximum power arm(1) when the dynamic action point is determined, the line of the fulcrum to the dynamic action point is the maximum power arm;(2) when the dynamic action point is not specified, we should see which point on the lever is farthest from the fulcrum, and then the distance from this point to the fulcrum is the maximum power arm.
Before the experiment, the balance nut of the lever should be adjusted so that it can balance on the horizontal position. The purpose is to make the center of gravity of the lever fall on the fulcrum so as to eliminate the influence of the gravity of the lever on the balance. When the lever balance, the distance between the O suspension hook yards distance is the arm, and can leverage on the lattice number instead of the size of the arm.
