Calculating Law of Levers Moments

[The P-manator]

When you calculate the two moments for the law of the levers, they are supposed to be the same, right?

 

[HallsofIvy]

I think you had better give us more information on the problem! My first thought was that if you are talking about two different moments on two different levers, then, no, they don't have to be the same!

I like to think of it in terms of conservation of energy: Work done on the lever is the force you apply times the distance that end of the lever moves and that must be equal to the work done by the lever: the force the lever applies times the distance the end of the lever doing the work moves. I think you will find that that is the same as saying that the two moments (of the two ends of the same lever!) must be the same.

 

[charng]

Yes, according to the law of levers, the two moments (or torques) should be equal when the lever is in equilibrium. This is because the law of levers states that the product of the force applied and the distance from the fulcrum to the point of force application on one side of the lever should be equal to the product of the force applied and the distance from the fulcrum to the point of force application on the other side of the lever. This is known as the principle of moments and is a fundamental principle in mechanics. If the two moments are not equal, then the lever will not be in equilibrium and will either rotate in one direction or the other. Therefore, it is important to ensure that the two moments are equal when designing and using levers in various applications.