in this video we're going to be looking at mechanical advantage and there are a number of things that AQA require you to know first of all is a definition so let's have a look at what that means so mechanical advantage there as you can see is the ability of a lever system to move a large load with a small effort and this nextt in bracket is also really useful for you to know because it's explaining why there is the mechanical advantage and that's because the effort is further away from the fulcrum than the load let's have a look at a diagram of a lever system and we'll bring this bit to life and hopefully that will help you understand further this principle of mechanical advantage so here's our lever system now we've got the fulcrum the load sometimes refer to resistance remember and the effort now something else that you may have come across in your teaching I want to just share with you now here is an easy simple way for you to remember what type of class of lever each one is that you might see so you may have seen this before so it's really quite straightforward 1 2 3 fle or fle E1 23 the fle here is representing the component of the lever system which is in the middle so for a first class lever the fulcrum is in the middle for a second class lever the load is in the middle and for a third class lever the effort is in the middle so if we look at this lever system here we can see that load is in the middle so L for two so therefore we can be sure that this is a second class lever the other thing that you are required to know is you required to draw up and label the different classes of lever and you're expected to know what the effort arm and the resistance arm is so if we look at the fulcrum here and we look at effort here if we draw a line between the two that is referred to as the effort arm and similarly from the fulcrum to the load or the resistance this is called the resistance arm so it might well be that you get a diagram which is half completed as I've just shown you and you're asked to identify and draw in both the effort arm and the resistance arm let's look at what else the exam board require you to know so they need you to know how to calculate mechanical advantage and it's calculated like this so it's mechanical advantage equals F arm divided by resistance arm now in the past we've seen past paper questions which take the form of multiple choice where you given a statement which of these or the question is which of these is the correct way to calculate mechanical advantage and there've been four different equations and they've been very very similar except they say one might say mechanical advantage is f arm plus resistance arm or F arm multiplied by resistance arm or F arm minus resistance arm so just make sure that you remember and you understand that mechanical advantage is fer arm divided by resistance arm okay so let's move on and have a look at another example so I'm going to change the lever system now so you can see that the load is now on the outside the forrum is on the middle is in the middle and the effort is on the outside as well so what I'd like you to have a think about is which type of lever system is this and how do you know so maybe just pause the video have a little think so you can see that the forcum is in the middle which means with our fle e123 system that because the forcum is in the middle this is a first class lever so again you can see that the resistance arm is relatively short so from fulcrum to the load the resistance arms is relatively short and yet from the fulum to the effort the effort arm is longer so here's a question for you high or low mechanical advantage does this lever system you can see in front of you have a high or low mechanical advantage and the answer is high and the question for you is why have a think about why it has a high mechanical advantage and again if we think about it the answer is because the effort arm is further away from the forcum than the load so the effort is further away here than the load is and that's what gives it high mechanical advantage if we change the structure slightly you can see this time that we've got a long resistance arm and a shorter effort arm if I ask you the same question the answer this time is low and hopefully you recognize the reason is because the effort arm is shorter than the resistance arm so the effort is closer to the forrum than the load is let's have a look at one more bit of a change around we've got a very long resistance arm here and we've got a relatively short eer arm so it's a third class lever how do we know that because we can see the fer is in the middle so with 1 2 3 f l e e is the effort which is in the middle which makes it a third class lever so again High low mechanical advantage looking at the resistance arm that's really long the eort arm is short so it's low and again why because the effort arm is shorter than the resistance arm so the effort is closer to the fulcrum than the load is now additionally another thing that you might be asked to do in your exam is to label or identify the names of the arms so you can see We've Got A and B here before we do that though let's just remind ourselves which type of lever system this is we've got the fulcom in the middle so therefore you will be recognizing this is a first class lever so exam type question what's happening at a what's happening at B hopefully you'll be able to recognize quite quickly the a is the resistance arm and B is the effort arm let's have a look at another class lever this time load is in the middle so hopefully you recognize that if this is a second class lever if we look at a with a very long arm there a is the effort arm and B is the resistance arm and finally we've got load on the outside we've got effort in the middle we've got fulum on the outside of the other end so this is a third class lever and again a is the resistance arm and B is the effort arm