a. Moment
In many tool engineering tool that can be used to alleviate or help with the work, for example, open a nut or bolt, to unlock the nut or bolt that is the way play it and like where if the rotating nut or bolt is done with bare hands? Weight is not it! So easy to open a nut or bolt is then used keys. The force exerted on the lock with a short stalk and long stalks when opening the same bolt will feel different.
Lightweight and weighed when opening the nuts and bolts depending on the length and the short stalk the key, the longer the key used stalk then unlock the bolt will feel lighter, it dikerenakan moment. Tool engineering tools that take advantage of the moment, among others: the lever, the player rods, crank, jack, pulley / pulleys, brake pedal and tools other tools.
Moment is the product of the force by the distance from the force to the point. If the style is given the symbol F and the distance from the style of the point is L, the moment can be written:
M = FXL …………………………. (1)
Figure 3.2 The principle of moments
To distinguish the direction of the moment, various kinds of moments consists of:
1) positive moment
Positive moment is a moment that has to right direction or in the direction of clockwise.
2) Negative Moment
Negative moment is a moment that has the opposite direction to clockwise.
Consider the following picture:
Figure 3.3 Various kinds of directions moments
b. Coupling
Coupling that two forces are equal, parallel and opposite direction with different fishing spot. If both styles each is F with a distance L, the amount of coupling, namely:
K = FXL ………………… .. (2)
Figure 3.4 The principle of coupling