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AQA physics UNIT 3 monday 30th jan 2012

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Reply 60

Unknown505

Hello Anyone what did you write for the bodes law questions????????????????

Reply 61

CaptainJim

Ok, so doing this made me go :confused:

and now I'm at a :eek:

Very hard, hoping for grade boundaries to be as low as the *something thats low*

I got 3 for the magnification and the time base was 0.000005.

Reply 62

VY Rose

Original post by mazam

I wrote 15 as well though I'm not sure if its right. :frown:

Also how did you get the answer 3.14 for the magnification?

And 0.15m for the screw question, don't you have to divide it by two. As 0.15 is the distance there and back and you want the distance to the crack.

I'm pretty sure it isn't, I'm afraid. Oh well!

Magnification was image height / object height. :smile:

Yeah, probably did actually... I do far better on the more difficult A level papers than I do on these... :colondollar:

Reply 63

VY Rose

Original post by CaptainJim

Ok, so doing this made me go :confused:

and now I'm at a :eek:

Very hard, hoping for grade boundaries to be as low as the *something thats low*

I got 3 for the magnification and the time base was 0.000005.

Yeah, so it was 6000 x 0.0000025 = Distance there and back. So dividing this by two would have been the right answer I suppose! Unless it wanted the total distance traveled by the wave? :colondollar:

What were the Bode's Law questions on? I've forgotten :tongue:

Reply 64

LtCloud

I felt that the timebase question was unfair considering they added a key of:

1cm = 0.000005, while in actuality each square was 0.5cm (measured)

Because of which I times the timebase by 2.5CM rather than 5CM and got a the answer that way.

I was thinking about going the other way but then assumed they put that there to trick people up, looks like it was the opposite to what I was thinking.

Now tell me how that has anything to do with testing our scientific ability? :angry:

Reply 65

mazam

Original post by VY Rose

I'm pretty sure it isn't, I'm afraid. Oh well!

Magnification was image height / object height. :smile:

Yeah, probably did actually... I do far better on the more difficult A level papers than I do on these... :colondollar:

What were the two numbers you divided to get 3.14?

Reply 66

CaptainJim

Original post by mazam

And 0.15m for the screw question, don't you have to divide it by two. As 0.15 is the distance there and back and you want the distance to the crack.

Yep, the grade boundaries better be low :mad:

Reply 67

Manunited_96

Bodes law I put yes because the calculations where similar to the actual distance, then the one about a planet in between mars and Jupiter at 2.8Au I said that the scientists opinion would change because the predicted distance was the same as the actual distance, the last one I didn't know i said the calculation may have been outdated and the orbits may have changed :/

Reply 68

sandeater

what did you write for the transformer question about the radio? i put so it could be used at home for domestic use as the voltage is stepped down?

Reply 69

krishman

hang on though - wasnt the sound question 6000m/s so therefore you had to divide the answer by 100 to get it in cm ?

Reply 70

Manunited_96

The voltage had to be stepped down so it didn't blow up

Reply 71

luke

Original post by MrLegendary

hey guys, new here, what answer did you get for the magnification? something along the lines of 3.14 ??

I got 0.5714.............
erm

Reply 72

luke

Original post by sandeater

how did you get 0.15m for the front of the screw i spent ages trying to do it but i couldn't explain?>???

I got 0.075 don't you have to divide it by 2 because it's there and back?

Reply 73

luke

Did anyone get something like this for the ray question?

Everyone got 3.14 for the magnification apparently, am I the only one who got this and 4/7 = 0.57 for the magnification

Reply 74

Ralphyboy

Original post by luke

I got 0.075 don't you have to divide it by 2 because it's there and back?

Damn! I forgot about that.

Reply 75

Zaii786

Original post by luke

Did anyone get something like this for the ray question?

Everyone got 3.14 for the magnification apparently, am I the only one who got this and 4/7 = 0.57 for the magnification

No dont think thats right sorry...Firstly it said you have to only draw 2 rays, and secondly, the green ray should go through the focus on the right side and im not sure what the yellow one was... then you have to trace the rays back and a virtual larger image is formed on the left :smile:

you got one ray right so hopefully youll get at least one mark for that!

Reply 76

Ralphyboy

Original post by luke

Did anyone get something like this for the ray question?

Everyone got 3.14 for the magnification apparently, am I the only one who got this and 4/7 = 0.57 for the magnification

I think here you got confused between a lens and a mirror. You will probably get a mark for the middle ray, and another if you remembered to put the the arrows on the rays.

Reply 77

VY Rose

Original post by Zaii786

you got one ray right so hopefully youll get at least one mark for that!

Not forgetting that an image magnified by 0.57 would be smaller! :P

Reply 78

VY Rose

Original post by Manunited_96

Very similar to what I put :smile:

Going back to a previous point, I agree that they test stupidly. Why not just ask us for loads of memorable information, instead of trying to screw us over with odd question wording! :P

Reply 79

Big_Ben

Original post by FiGuev

pulse a was the crack and pulse b was the back of the screw

That's what I got...I'm surprised...everyone thought it was a hard exam but I didn't! The last question I found really easy aswell it's just total anticlockwise moment = total clockwise moment and you could work it out from there...! For the last one I got 375 N...