That is exactly what I said. ??? I am guessing you are still stuck. Ask again if you are.
I think I just didn't get your wording (I hate the worded questions on this unit because I don't understand what they want!) until I got the link between the ship's motion and the force. Many thanks for your help
Do you mind also explaining question 3bii on the Jan 12 paper? I don't understand what the mark scheme expects you to write from the first 2 marking points written (I wrote the stuff below about maximum thrust, resistance increasing with speed and drag eventually equaling thrust).
The mark scheme says "correctly linked" but what are you supposed to write?
lets say the distance between the centre of 2 adjacent slits is 'd' which can be worked out by doing . so as the wavefront of the source comes in, it diffracts at an angle towards the screen, this can be calculated by using a protractor or a spectrometer. if you get constructive interference you know that the path difference for say the first order is . now using some trig, we know that . sub in and 'd' to give . which gives . now for every maxima or order on the screen, that means you are getting constructive interfence, therefore the path difference with always have to be a whole number (integer) multiple of , so lets call that . therefore you get
I think I just didn't get your wording (I hate the worded questions on this unit because I don't understand what they want!) until I got the link between the ship's motion and the force. Many thanks for your help
Do you mind also explaining question 3bii on the Jan 12 paper? I don't understand what the mark scheme expects you to write from the first 2 marking points written (I wrote the stuff below about maximum thrust, resistance increasing with speed and drag eventually equaling thrust).
The mark scheme says "correctly linked" but what are you supposed to write?
Guys, why is question 7ai on the June 2009 paper worth 4 marks?! Isn't it just a simple equation that we have to use?
Yes, you have to use dsintheta=n lambda. They said 2nd order (1 mark), correct equation (1 mark), correct calculations (1 mark) answer to 2 or 3 sf only (1 mark).
I think I just didn't get your wording (I hate the worded questions on this unit because I don't understand what they want!) until I got the link between the ship's motion and the force. Many thanks for your help
Do you mind also explaining question 3bii on the Jan 12 paper? I don't understand what the mark scheme expects you to write from the first 2 marking points written (I wrote the stuff below about maximum thrust, resistance increasing with speed and drag eventually equaling thrust).
The mark scheme says "correctly linked" but what are you supposed to write?
Basically, when it says 'maximum horizontal velocity', it means the point at which the aircraft reaches uniform motion in the horizontal direction (no resultant force acts upon it, newtons first law). Thus, an object with a larger surface area is affected more by air resistance. So it terms of this question, you gotta link in the large surface area of the aircraft, to how air resistance affects it, and so reduces the maximum horizontal velocity it could achieve.
That makes sense, but how does that answer the question? Is it not the fact that the plane is affected by air resistance, rather than what features of the plane affect air resistance, that limits the maximum horizontal velocity?
Ok here is the rule! There will be only one question where they will test you on the significant figures. For the rest of the question, look at the quantity they have given you. EG, 3.2x10^7kg is to 2 sf. This means they are looking for 2 s.f. answers. Is that ok?
Yeah, I'm okay with the ones where they say "an appropriate number" its just the others, I used to do 3 because of maths but I'll do two now, thank you
Yeah, I'm okay with the ones where they say "an appropriate number" its just the others, I used to do 3 because of maths but I'll do two now, thank you
haha i agree with you on that one, maths they always want it in 3 s.f. so it does get confusing
Yes, you have to use dsintheta=n lambda. They said 2nd order (1 mark), correct equation (1 mark), correct calculations (1 mark) answer to 2 or 3 sf only (1 mark).