Observer standing of the platform

What does it tell in terms of the velocity of the speed of the observer guys we haven't read somewhere where they are talking about the speed of that observer okay so which means this information standing on the platform it's enough for us to conclude that the velocity or the speed of the listener or the observer is 0 meters per second very much important ladies and gentlemen. Why am I confident that the speed or velocity of the listener at zero meters per second is because ladies and gentlemen 

they just indicated that the observer or an observer is standing on the platform and from there they never said anything regarding the speed or the velocity of the observer okay very much important ladies and gentlemen that you take into account this kind of information this is not the only way in which they can represent a stationary or a standing observer ladies and gentlemen they can for example give a situation where there's a car accident and an ambulance is approaching the scene so ladies and gentlemen you should be aware very much important that you should be aware that there are different ways in which they can explain or guide you in terms of the velocity of the listener okay of the listener of an observer or a detector whatever that is it depends on the information or the scenario that you're given 

ladies and gentlemen. Let's now continue so I assume you fully understand that so I did it on purpose ladies and gentlemen I just explained everything and left out that information regarding the observer why it's because I wanted you to actually notice that not all the information that I'm providing is limited or it's all that is necessary for you to you know to reveal oh a ladies and gentlemen to a you know dish out to you can go beyond the information that I've provided okay.

So guys let's now start with our very first question ladies and gentlemen so the question which is 6.1 says name the phenomenon that explains the change in page head by the observer and this question is allocated one mark ladies and gentlemen in this case examiners are not only interested in you providing an answer guys it's very much important that when you start each and every question you know the chapter of that particular question okay they cannot mix this a chapter with that of as an example ladies and gentlemen 

vertical projectile motion in one dimension okay I'm just giving that as an example to say a they might not really incorporate or combine this chapter with that of work energy and power okay very much important ladies and gentlemen so lastly guys they might not combine this chapter with that of electric circuits okay so there will be a chapter for electric circuit there will be a chapter for a vertical projectile motion there will be a chapter for work energy and power so ladies and gentlemen. Learn to differentiate those type of chapters okay 

so that you are able to then answer questions related to that particular chapter for example in this case guys they say name the phenomenon okay that explains the change in peach head by the observer okay so obviously some of you already know an answer to this question but what I wanted you to notice ladies and gentlemen is that it's very much important that you really know and understand the chapter that you're about to start with okay so for the purpose of answering this question and answer to that question ladies and gentlemen is Doppler effect.

So what is Doppler effect ladies and gentlemen it's the phenomenon okay it doesn't necessarily mean that I'm actually giving the definition of a Doppler effect but I'm just trying to indicate to you that this may be a question in multiple choice type of questions which may be asked to use such that you need to choose from multiple choice or the list given and you then need to choose double effect as an answer for that question in the multiple choice type of questions. So that means you should be aware that a phenomenon that explains the change in pitch heard by the observer can you see how general the statement is ladies and gentlemen. 

Phenomenon that explains the change in peace heard by the observer even if I didn't draw all of that information ladies and gentlemen even if I didn't read all of this given statement ladies and gentlemen and only read the question you should be able to know that the phenomenon that explains the change in pitch heard by the observer it's Doppler effect okay so remember this question is allocated just one mark so let me just write down this is question six and you are advised to start this question on a new page very much important ladies and gentlemen so now we are still on question 6.1 in answering the question ladies and gentlemen just write 6.1 and say Doppler effect. Very much important ladies and gentlemen by so saying you score yourself one mark okay so we will make sure that you get that mark ladies and gentlemen because you you've actually answered you know you've actually fully answered the question. 

Okay so guys I think we can now move to the next question okay very much important ladies and gentlemen that we write all these answers so that in case if you're writing down you can just note it down at a later stage when you prepare for your exams you can still refer to the same information. Ladies and gentlemen there is a question which is 6.2 and the question says calculate the frequency of the sound that the observer hears while the train is approaching him. Use the speed of sound in air as 340 meters per second very much important ladies and gentlemen that you fully understand what the question wants you to calculate okay very much important ladies and gentlemen there are situations where a you might need to calculate whatever that the question might want you to calculate.