Okay so guys can i just add there to say that cable it's moving at a constant speed of four meters per second okay ladies and gentlemen just to give you a hint if it's moving at a constant speed of 4 meters per second so that means its initial velocity and its final velocity will be the same okay very very much important ladies and gentlemen so just in case if you need to solve or answer a particular question and you you know you get to a stage where you realize the formula that you must use has got initial velocity and final velocity then because it was indicated that the cable is moving at a constant velocity or at a constant speed then it means its initial and final velocity is the same very very much important ladies and gentlemen.
Okay so now uh the tension in the cable i've just explained is also given there it's 960 okay so i'm i'm getting to a part where i'm interested in so they're saying i assume that there is no sideways motion during the lifting okay very very much important ladies and gentlemen remember assuming that this is that a aeroplane ladies and gentlemen this is that aeroplane and this is that cable okay a if this is a cable ladies and gentlemen for example let's say it's a a it's a steal let's let's just say it's a steel okay so it's just vertically moving upwards unlike if it was a a
let's say a rope okay you know a rope it can be bending somehow as a result of a wind and again if this aeroplane it's not stationary at one point maybe a slightly moving sideways and again slightly moving up and down that's when you can have a you know a rope this is that person a the soldier that's when you can have a rope moving sideways okay but in this case they're saying this is stationary at one point not moving sideways not moving up and down the only thing which is moving is just that cable okay and the tension is 916 newton.
Ladies and gentlemen that's that means a there's only one upward movement okay so a that cable is not in any way moving side ways okay very very much important ladies and gentlemen if it was moving sideways then it was going to have a an impact in terms of the forces as a result of its moving um sideways okay so what could possibly make that a cable or a rope to move sideways it's wind ladies and gentlemen if there's a strong wind then it could possibly move sideways but the statement says assume that there is no sideway motion during the lift okay i assume you fully understand that part.
Ladies and gentlemen so again they say a friction is not to be ignored very very much important ladies and gentlemen please read this statement in full i know in most of the questions they would say air friction to be ignored okay but in this case they say a friction is not to be ignored okay this is very very much important ladies and gentlemen it's massively important that means as this soldier is being lifted upwards there is a friction as a result of a not sure if you understand.
Ladies and gentlemen there's a friction as a result of a okay i i assume someone already understands that there is a force of friction as a result of a okay so ladies and gentlemen i'm not really sure if we are all ready to now start uh tackling these questions i assume the moment you see a diagram similar to this one you won't be worried you won't panic you'll just have a look at what is given and i can tell you ladies and gentlemen this statement and the the diagram it it's actually there to help you to write or to draw the correct free body diagram because once you get the the free body diagram correct i can tell you ladies and gentlemen your formula is going to be correct your substitution should be correct in that way you will be able to a you know find the correct answers and in that way you will be able to score maximum marks.
Okay so ladies and gentlemen i'm just going to uh read through the first question and the question says state the work energy theorem in ways and this question is allocated to max okay i'm sure most of you you already know the answer because you've been reading you've been studying a lot you've read multiple books where they've stated the wake energy theorem in ways so i'm just going to quickly a state it so that you are able to then compare okay so this question is allocated to marks.
Guys so i'm just going to wipe all of this and then from there we'll start with our very first question which is question five a point one okay so ladies and gentlemen normally in physical sciences when they request you to state either the the you know the theorem they they could be saying a define whatever that it is ladies and gentlemen what matters the most is that you are able to know the chapter that you are dealing with okay so some chapters if you can just check the formula sheet they will guide you in terms of how a you know in terms of how to define or to state theorems you know so it's very much important that you know the chapter that you're dealing with and again you know there are you know the formulas associated to that particular chapter in the formula sheet okay you remember ladies and gentlemen we've got a formula which says a work net it's equals to change in k or delta k.
Okay which of which we know delta k is actually the it refers to the kinetic energy okay so ladies and gentlemen for me i know i'm dealing with this chapter okay of work energy and power so i can just go to the formula sheet and look for this formula and and you know state the theorem while being guided by this formula okay which means the net work done on an object ladies and gentlemen i've just stated that part very very much important ladies and gentlemen.
The net work a done on an object in this case which could be a soldier is equals to the change in kinetic energy of the object ladies and gentlemen eh is equals to okay it's equals to the change remember this is the change ladies and gentlemen in greek is called delta okay in english is change okay so it's equals to the change in kinetic energy we know k reference to kinetic energy ladies and gentlemen okay kinetic energy of the object okay so that's all i'm saying ladies and gentlemen in physical sciences you just need to know the chapter that you're dealing with you go to the formula sheet you check the formula and then from there you just use the formula to do whatever the question wants you to do okay.
So i'll just write it down but for you to know of the trick in this question or a what is it i'm i'm i'm not actually a you know i don't think calling it a trick it's it's a suitable weight but instead let me say the advice is that as soon as you're given a question where they want you to give a definition to describe or to state the theorems in ways this is where you need to know the chapter that you're dealing with go to your formula sheet look for the relevant formula write it down and use it to give a description okay so that means an answer to the question is we can just say the net work done on an object.
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