Hello guys my name is Desmond and i welcome you to my youtube channel ladies and gentlemen uh as you can see today we'll be looking at physical sciences paper one the chapter for work energy and power so guys please do allow me to say it's very much important that i say it's very very much important because ladies and gentlemen what i'm about to say it's massively important.
Okay so a day without learning something new it's a day wasted by so saying i would encourage each of you to make sure that by the end of each and every question or by the end of the whole of this question please do make sure that you learn something new okay so ladies and gentlemen without any waste of time as you can see we're given a statement for question five and also you are advised to start on a new page okay so what i'm going to do is to quickly to read through the statement from there what we're going to do is just to a you know quickly analyze the given diagram go through each and every question solve the question and most importantly i'm going to show you where you score your marks.
Okay so ladies and gentlemen let's not waste any more time so as you can see a question number five i'm going to read through the statement so a rescue helicopter is stationary in brackets hovers above a soldier the soldier of mass atkg is lifted vertically upwards through a height of 20 meters by a cable at a constant speed of 4 meters per second the tension in the cable is 960 newton assume that there is no sideways motion during the lift air friction is not to be ignored a friction is not to be ignored.
Ladies and gentlemen it's very very much important that you fully understand exactly what is going on there and most importantly it's very much important that you fully understand what the given statement instructs you to do what to note and what not to know then most importantly what to ignore and what not to ignore so ladies and gentlemen before i start with the interpretation of that given statement that i've just read i would like to just indicate that this lesson is suitable for grade 11 and grade 12 and again if you are upgrading this subject you're also welcome to watch this lesson.
And i hope you will enjoy this lesson so ladies and gentlemen as you can see i've tried to draw by hand this diagram remember guys at all times it's not by intention to make it perfect but what matters the most it's for it to look more or less the same and most importantly have those values in place over there okay so guys for the last time i'll just read through as i explain so ladies and gentlemen we've got a rescue helicopter which is stationary above a soldier okay so that means this helicopter that you see ladies and gentlemen it's not moving in any direction it's not moving forward or to the left it's not moving to the right it's not moving upwards it's not moving downwards but it's stationary at that point.
Obviously it's hovering because uh you know it's it's in the middle of the hair the a okay so ladies and gentlemen what happens is you've got a soldier of atkg okay very very much important ladies and gentlemen that you notice on that sentence you're actually given the mass of the soldier and most importantly ladies and gentlemen in physical sciences we measure the mass in kilograms okay so just in case if that mass was given in grams then that means you will have to convert it to kilograms and obviously when you convert from grams to kilograms you divide by a thousand remember ladies and gentlemen kg it's the mass or the unit in which we measure the mass in physical sciences.
Again a you know kilo means thousand very very much important ladies and gentlemen so they're saying a soldier of mass 80 kg is lifted vertically upwards through a height of 80 meters by a you know by a cable at a constant speed of four meters per second okay very very much important ladies and gentlemen i'm not really sure if i should add that information there because as you can see we're also given the speed at which um you know that that cable is moving okay and most importantly guys please do take note of the letters used on the statements okay they've just said cable at a constant speed in capital letters very very much important.
Ladies and gentlemen in capital letters okay so it gives you a you know it serves as a hint that some way in your questions you might need to refer back to that statement and what you need could be that constant speed in capital letters so my advice to you guys every letter is very very much important and the manner in which those letters are presented in the statement they should be telling you something okay so everything is written in small letters but that part is written in in capital letters so just make sure that you stand up i mean you stay with me until the end of this lesson because i need to show you exactly why that is important and again why it was written in capital letters.
Okay so ladies and gentlemen i assume you are able to see clearly so just to remind you guys if you are not able to see exactly uh what i'm reading or if a on the screen of your phone tablet or computer or whatever that you're using could be laptop or whatever it is um on your phone i think on the top right corner there you've got some three doors there if you can just click there and click on quality down there you click on advanced and then you maximize the quality i'm not sure if it's 480p or 380p but as soon as you click on that you should be able to clearly see each and every letter on my tablet.
But otherwise if you're not able to see remember i post this question papers on my telegram channel so you can quickly access this question paper okay but for now i need you guys to just pay full attention uh you just need your calculator and a glass of water no need to write anything as i write because i'm going to make this lesson available as soon as we are done with this lesson okay so ladies and gentlemen very very much important that you understand and again you see what i'm talking about so now you've got this guy which is a soldier of mess atkg okay so now we've got this cable which is pulling upwards at a constant speed of 4 meters per second and again the tension in the cable is 960 newtons...
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