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AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread]

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Reply 2720

SuperMushroom

Original post by StarvingAutist

No, you add it. The largest distance is when the earth is on the opposite side of the sun compared to.. the thing

Ahh ok seems I got that wrong then

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Reply 2721

Hellomoto.

Original post by lad123

For the questions it said show that the value is 'about' x, such as show it was 1.4*10^-15 m and you get 1.43*10^-15, for the next part in the questions do you use 1.43 or 1.4? or doesn't it matter?

they accept both answers :smile:

Reply 2722

fruity97

Original post by superduperbob

I put main sequence

I put main sequence as well in the end after changing from dwarf star, people at my school saying dwarf but I thought the power output was way too high to be a dwarf star :frown:

Reply 2723

QueNNch

Original post by StarvingAutist

No, you add it. The largest distance is when the earth is on the opposite side of the sun compared to.. the thing

Yup!
I added 1AU + 2.57AU (largest distance) to get something like 3.57AU to get the largest possible distance.

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Reply 2724

SuperMushroom

Original post by fruity97

I put main sequence as well in the end after changing from dwarf star, people at my school saying dwarf but I thought the power output was way too high to be a dwarf star :frown:

I thought this aswell

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Reply 2725

k9000

Anyone get 2.07x10^6 m2s-2(might have been 7 cant remember) and get 4.7x10^4Jor around that?

Reply 2726

wat a wizard

Original post by fruity97

I put main sequence as well in the end after changing from dwarf star, people at my school saying dwarf but I thought the power output was way too high to be a dwarf star :frown:

i used the fact that its power output is similar to the sun, but much hotter

Reply 2727

superduperbob

Original post by SuperMushroom

I thought this aswell

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I did it based on temp, it was 5,000K which is an orange star, so therefore it should be a main sequence star

Reply 2728

HenryHein

Original post by k9000

Anyone get 2.07x10^6 m2s-2(might have been 7 cant remember) and get 4.7x10^4Jor around that?

I think I may have had 2.06x10^7 but otherwise yes I concur for both

Reply 2729

QueNNch

Original post by k9000

Anyone get 2.07x10^6 m2s-2(might have been 7 cant remember) and get 4.7x10^4Jor around that?

Yeah something like that for the mean square speed :smile:

But my energy was different... It was like 1.6*10^7 :frown:

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(edited 8 years ago)

Reply 2730

bwr19

Original post by SuperMushroom

For the first question on astro as it gave the distance from the sun in AU and it wanted the distance to the earth so do you take away 1AU from the largest distance given and this would give the distance to the earth

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That's what I did. 2.57-1 AU and convert to metres. Hope that's right. I presume it wanted the distance between the centres and we didnt have to remove the radii.

Reply 2731

lad123

Original post by dominicwild

I initially thought this too. But I looked at the units, which were

Unparseable latex formula:

m^2s^-^2

So I calculated the mean. Then I just squared it all.

Oh ok i have no clue if im right, i just remember when you derive the pressure of a gas (u1^2 + u2^2...) / Number of particles = mean squared value

Reply 2732

RemainSilent

Original post by HenryHein

I think it said largest distance, so you add 1AU not take away (3.57AU in total?)

did what i di !!!! many say taking away is right but surley if the earth is behind the sun and venus or whatever the distnce is add 1 ?

Reply 2733

GuyPerkins1996

Original post by Sbarron

Now I'm far from the best student so DON'T go by these values but I just want to see if anyone got any the same as me.....

Nuclear and thermal:
0.05, 5.00
1.4*10-15 m
5.3*10-15 m
1.3*10^17 kgm-3
3.3*10-6 s-1
8.2*10^11
47000J
160000
319 K

Astro:
2.4*10^11
15m
-82
5000 K
97*10^6
8.8*10^21
4.9*10^17

I agree pretty much with all the Thermal and Nuclear ones! I did turning points section 2 though :3

Reply 2734

Faaiz Shah

Anyone get 24 volts in thermal and 250 muons in option d??

Also one question said shouw its 4 to something i got like 4.12... To the something

Reply 2735

dominicwild

Original post by Lizzieee4

It was related to Charles' law or the pressure law I think

I was thinking something along those lines. I just couldn't think how you'd do it experimentally. I just stated that you'd keep pressure constant and slowly squished some area (with a piston) with a constant amount of gas. Measuring temperature in K as you do it. It should regress close to 0 or -273 in C. Which defines absolute zero as its the lowest temperature you can get to?

I didn't write much at all, just attempted to cover all bullet points.

Reply 2736

bwr19

Original post by dominicwild

I initially thought this too. But I looked at the units, which were

Unparseable latex formula:

m^2s^-^2

So I calculated the mean. Then I just squared it all.

Nooo.. you calculate the mean of the square values, not the mean of the values and then square it all.

Reply 2737

QueNNch

Yep you add the distances because maximum distance is when earth is on opposite side of the vestra(?) asteroid.
Something like 3.57AU

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(edited 8 years ago)

Reply 2738

bwr19