# General Thoughts: Physics (1 Viewer)

#### Sarah Jane 1

##### New Member
i did the same and got the same answer

#### malcolm21

##### Active Member
that was a different question wasnt it, you wouldnt have to derive it
but for the 6 mark space one, it would have been good to explain that orbital & escape velocity are derived from the universal gravitation law
oh alright, do you know why the one im thinking about was worth 3 marks? you literally do it in one line. For that 6 marker did you talk about how the planets are attracted by the sun and orbit it and stuff

#### p0llex

##### Member
What's qV? I equated work and kinetic energy (as work is equal to the change in kinetic energy). So Fs = 1/2mv^2 or qEs = 1/2mv^2. Answer came out to 4.1x10^7
Yep my mistake I got that too, I was thinking about the velocity of the satellite

#### vflaash

##### Member
v=7798 m/s for orbital velocity question
h= 2.5 metres for that wall in projectile motion question ?

#### Sarah Jane 1

##### New Member
What about the height of the platform for projectile?

#### KingDeezy

##### New Member
Someone pls post the paper

#### malcolm21

##### Active Member
i think the problem with this test was how vague some questions were in terms of what they were looking for. But I'd assume that's to seperate those who rote learned and those who do actually conceptually understand content

Referring to the last 6 marker of the test

Couldn't you have just found acceleration first through a=f/m, then used it to find final velocity upon hitting anode through v^2=u^2+2a(delta y)
u can, i did that and got his answer, i got 4.2 *10^7, do you know what u got

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#### p0llex

##### Member
v=7798 m/s for orbital velocity question
h= 2.5 metres for that wall in projectile motion question ?
Yes to both

#### jackleung34

##### Member
oh alright, do you know why the one im thinking about was worth 3 marks? you literally do it in one line. For that 6 marker did you talk about how the planets are attracted by the sun and orbit it and stuff
need more detail on which question youre referring to. I don't think i wouldve gotten full marks, but I talked about all of Newtowns laws, relating it to slingshot and travelling between planets. Brough in universal gravitational attraction to emphasize sling shot. Hecticlad talked about Vescape and such which I dont think I touched on. They do open alot of avenues interms of relating it to universal gravitation and I don't think many would have been able to include everything listed already

#### keepLooking

##### Active Member
I fucked up guys. Band 5 would be a complete dream for me. Anyone feeling the same? I was on a tilt during the exam because this exam was quite different from the past papers ._.

#### malcolm21

##### Active Member
need more detail on which question youre referring to. I don't think i wouldve gotten full marks, but I talked about all of Newtowns laws, relating it to slingshot and travelling between planets. Brough in universal gravitational attraction to emphasize sling shot. Hecticlad talked about Vescape and such which I dont think I touched on. They do open alot of avenues interms of relating it to universal gravitation and I don't think many would have been able to include everything listed already
the one where the satellite was lifted 200km above earth radius, i did v =root/6.67*10^-11 * 6*10^24/(6380000+200000) if i recall correctly, so one line

#### keepLooking

##### Active Member
the one where the satellite was lifted 200km above earth radius, i did v =root/6.67*10^-11 * 6*10^24/(6380000+200000) if i recall correctly, so one line
Yeah. It was a 3 marker for the a 'simple' orbital velocity calculation.

#### IamKirby

##### Member
I fucked up the orbital velocity question, the single easiest question in the paper.

Sent from my iPhone using Tapatalk

##### Member
oh alright, do you know why the one im thinking about was worth 3 marks? you literally do it in one line. For that 6 marker did you talk about how the planets are attracted by the sun and orbit it and stuff
well the escape velocity formula isnt on the datasheet, so if someone one didnt remember it then they would have to derive it which would probably be worth 3 marks
for the 6 mark, i wrote a lot of shit about the launch e.g. thrust, reduced mass from the fuel, escape velocity. i didnt have much time to write about the planets though, i wrote about the inertia of the rocket in space so they dont need to use fuel, and also the calculations needed to slingshot manouver with F=Gm1m2/r

#### jackleung34

##### Member
Yeah. It was a 3 marker for the a 'simple' orbital velocity calculation.
Most calculation questions are extremely formulaic where you have to have equation/sub/correct answer for 2 marks. I think for this one as Vorbital is not an actual equation on the formula sheet, the third mark may me from deriving the equation, where Fc=Fg. If not i have no idea where 3rd mark is RIP

##### Member
the one where the satellite was lifted 200km above earth radius, i did v =root/6.67*10^-11 * 6*10^24/(6380000+200000) if i recall correctly, so one line
mfw put the radius at 200000 not 6580000
fml, well the good thing about it being a 3 mark question is that i will most likely still get 2 marks cus i wrote out all my calculations and values and shit

#### keepLooking

##### Active Member
Most calculation questions are extremely formulaic where you have to have equation/sub/correct answer for 2 marks. I think for this one as Vorbital is not an actual equation on the formula sheet, the third mark may me from deriving the equation, where Fc=Fg. If not i have no idea where 3rd mark is RIP
it was ~ 7700 something right?

#### jackleung34

##### Member
wtf was that copper/ bar magnet graph holy fuck im pretty sure i got like 2/5 marks

it was ~ 7700 something right?
what i got at least

#### SlimiJay

##### Member
does anyone have the paper who could upload it?