[Music] hello and welcome to another gcsep related video today i'm going to run through a gcsep video that's targeted towards this year's examinations and please before we begin do not forget to subscribe to this channel and hit the notification bell so to begin with i would like to discuss the different parts that make up each of the lever systems you can see so you have a fulcrum which can also be known as the pivot you have the resistance which can also be known as the load and you have the effort i like to stick with the words fulcrum resistance and effort because i like to use something called fre123 and what that simply means is the fulcrum sits centrally of a first class lever system so that being my f r resistance sits centrally of my second class lever system and then finally e effort sits centrally of my third class lever system so f r e one two three what you also need to know is when you're asked to draw a lever system you have to draw an arrow to represent the efforts you have to draw a square to represent the resistance and you have to draw a triangle to represent the fulcrum now moving on from that if we have a look at the first class lever system we need to start thinking about sports and examples associated with it so a couple of examples that i might mention are movement of the neck forwards and backwards and in that particular scenario the fulcrum will be the joint that sits just behind the jawbone the effort will be the muscles in the neck and the resistance will be the weight of the head if i were to give you another example for a first-class lever system we might talk about a tricep extension or a football throw so in that particular situation the fulcrum will be the elbow because that's that's that's the joint that's where the movement occurs the tricep would be the effort because that's the muscle that contracts and produces the movement and the resistance would be either the dumbbell that i'm using or the football that i'm throwing for a second-class lever system we might start to look at the ankle in different scenarios so you could look at a calf raise you could look at the starting position when exploding out of the blocks in a hundred meter sprints you could also look at running in general so the fulcrum would be the actual ball of the foot where we see the crease in a person's trainer that would be the fulcrum because that acts as the joints the effort would be the muscle in the lower leg located at the back which is known as the gastrocnemius i'm sure you understand that and resistance would be the person's body weight for a third class lever system we'd start to look at something like a bicep curl so in this scenario the effort will be the bicep because it's the muscle that contracts and shortens causing the movement to take place the fulcrum will be the joint which is the the elbow and then the resistance will be the dumbbell the weight that the person is lifting as they perform the exercise and let's move on to mechanical advantage so a second class lever system has a mechanical advantage and the reason being is that the resistance arm is short this basically means that the distance between the resistance and the fulcrum is shorter than the distance of the fulcrum and the effort okay so there's a long effort arm here between the fulcrum and the effort what that means is when you perform an exercise like a calf raise the input force which is the effort is actually minimal but the output force is great so if i were to ask you to perform a card phrase now i'm sure you know from experience it's quite an easy exercise to perform and therefore it requires minimal effort but the outcome is great because it moves the entire body and moving on to a third class lever system it has a mechanical disadvantage because unlike the second class lever system it has a short effort arm instead of long so the distance between the fulcrum and the effort is short but the resistance arm is long so the fulcrum and resistance are further apart so for that reason it has a mechanical disadvantage thank you for joining me i hope you found it helpful good luck in your exams this year and please please please if you do have any questions or concerns please just share them in the comment section below i am more than happy to help thanks for joining me take care see you again soon