the mathematical method used in the principle of moments can get a little bit confusing at times but as long as you follow these steps i can guarantee that you will get the right answer every single time let's start by recapping what moment is moment is just the force applied times by the perpendicular distance to where the pivot is let's look at this example where we have a guy uh standing on one side of the seesaw and let's just say he's right at the edge and he is 1.5 meters from the pivot and we're told that his weight is 500 newtons so when this guy is standing on the seesaw he's going to tilt it towards the left-hand side due to his weight so the question is if we know that there's this other guy who whose weight is 600 newtons where must he stand on the seesaw in order to balance it so i'm just going to put this guy on the right hand side of the seesaw i don't know what the distance is so i'm just going to call it d and let's say this guy weighs 600 newtons so here we can use the principle of moments to work out what d is the principle of moments tells me that if a system is in equilibrium or it's balanced then the total clockwise moments must be equal to the total anticlockwise moments i'm going to write down this principle as the first line of the solution so the total clockwise moment is equal to the total anti-clockwise moment from this diagram i can tell that the guy on the right hand side is providing the clockwise moments i'm just going to annotate that and since moment is force times distance i can't take his weight as the force which is 600 times by the distance from the pivots in this case it is d that is our unknown so this is equal to the anti-clockwise moment which is caused by the guy on the left-hand side and his weight is 500 and the distance from the pivot is 1.5 meters let's work out what's on the right hand side first by multiplying 500 by 1.5 that's going to give us 750. in order to make d the subjects i need to divide 750 by 600 and that gives us 1.25 meters so just to summarize when solving using the principle of moments first state the principle of moments clockwise moments is equal to the anti-clockwise moments and then you need to substitute your numbers in and finally you want to rearrange so that you make whatever you're trying to find the subject so here's how you solve a problem using principle of moments hope your revision is going well be sure to subscribe for more physics