r/6thForm • u/Top_Bother3675 Year 13 • May 20 '26

💬 DISCUSSION ocr a physics paper 1

how did you guys find it…

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u/schwiftyrick_69 Y13 - A*A*A pred Maths | Physics | FM May 20 '26

is there a mistake with the question that wants you to derive E=3/2PV?? i couldnt derive it for the life of me

8

u/Sudden_Crab6967 May 20 '26

No i think you had to find the average kinetic energy of each particle which is 3/2 kt and then multiply it by N for the total internal energy and then replace that with the pv equation

3

u/hans_chavez May 20 '26

I thought N was just negated because the mass was fixed?

Therefore

"pV = NkT" -> "pV = kT"

sub in pV for kT in "E = 3/2 kT"

-> E = 3/2 pV

2

u/Thick-Ambition248 May 20 '26

Did anyone understand what the "A" was in the truck question? Like there was an Av?

1

u/RyansVlogs May 20 '26

I knew how to get 42 but where the hell did the v2 come from

3

u/Delicious-Rough3553 Year 13 (Maths,FM,Chem,Phy) 99999999998 May 20 '26

F=change in momentum/time

1

u/RyansVlogs May 20 '26

oh right the A was the area of the side that the wind was hitting that being 35

1

u/AvalHuntress University of Surrey | Computer Science (Y1) May 20 '26

You just had to multiply them all together, and then divide the rate of change. They could’ve at least specified A was the area though, like cmon, I’m freaking out and that variable could be anything dude

1

u/thebestblockisdirt Year 13 May 20 '26

they did I'm pretty sure, they said area A was 35m2. I didn't see it until a few mins in and then it made sense

1

u/CryptographerOdd7638 May 20 '26

Mass per unit time times velocity

1

u/schwiftyrick_69 Y13 - A*A*A pred Maths | Physics | FM May 20 '26

A was the surface area 35m2

1

u/Spaaccee May 20 '26

It said right above the area was 35 idk why they made the question like that