Physics Predictions/Thoughts (3 Viewers)

[C_master]

You have 7 days, which is 168 hours. counting 8 hours of sleep, that is 112 hours. So in reality that is a total of 4 days of actual work

you're asking for it

 

[C_master]

ngl I only realised today that you’re graduated

i thought i was the only one
thought that bloke was our cohort

 

[gossipgirllll]

ngl I only realised today that you’re graduated

aint no way hes doing ts for fun

 

[BionicMango]

ngl I only realised today that you’re graduated

Lol technically you have too

 

[BionicMango]

I get bored teaching year 7s how to find the area of a square

 

[Trial&Error]

Which HSC paper do we think was the hardest so far? I feel like they were all pretty similar.

Also what's like the hardest calculations question they can throw at us? From what I've seen they're pretty uncreative when it comes to calculations but super niche for explanation qs.

 

[BionicMango]

2019 was pretty hard but it’s also the first one in the syllabus so least creative ig
I haven’t looked at that one in a while though

 

[academic_reaper]

What do we think?

 

[Isit_actually?]

Bro, if they have another “Show that v= Root(GM/r)” question I swear I’m gonna lose my shit.
Like it’s not even hard — it’s just pointless. We’ve derived this thing a hundred times; it’s literally the same two steps:
Fg=GMmr2=mv2r ⇒ v=Root(GM/r)
But NESA acts like we’re unlocking a new law of physics every exam.
Miss one tiny line like “equating centripetal and gravitational force” and boom “-1 mark, insufficient working shown.”
Bro, I’m not proving relativity here, I’m just doing Year 8 algebra.

 

[coolcat6778]

Lol I'm pretty sure they can only ask you to derive what they told you to derive in the syllabus "Derive kepler's law".

NESA considers derivation of novel situations too advanced for the HSC Physics syllabus.

 

[C2H6O]

Like chem, my pred for last q:
“A 1000kg chromium spaceship wrapped in 300 copper windings of resistance 80Ω was connected to an adjustable power source and accelerated out of Earth geosynchronous orbit through a series of 200 radial magnetic fields of 3T produced by iron rings. The maximum magnitude of voltage applied each time the spaceship passed through an iron ring was 2400V. A stationary observer observes some light emitted by the spaceship as it reaches the end of the iron rings at a fraction of the speed of light.
You may assume all energy of induced eddy currents was transferred to the thermal energy of the chromium and that chromium behaves as an ideal black body. The specific heat capacity of chromium is .
Use this as a stimulus to discuss and evaluate the significance of unifying our understandings of physics to apply to the world around us with reference to past experiments and the law of conservation of energy.” (7 marks) (*mark to effort ratio is completely off as usual*) (*2 full pages of lines but you’re expected to also use all 4 pages of extra space cause why should NESA give you enough space*) (*criteria will also require full mechanical, orbital, electromagnetic, thermodynamic, relativistic and quantum calculations despite all indications that a written response was expected*) (*if you didn’t have at least 3 pros and 3 cons of some sort doesn’t matter what cause they don’t even know what you need to argue you will lose all marks cause they were all allocated to evaluation*) (*if you didn’t refer to at least 3 past experiments cause they gave plural but its physics so plural means 3 you get 0*) (*if you didn’t refer to conservation of energy enough that’s a 0 cause what are you doing*)

 

[coolcat6778]

Like chem, my pred for last q:
“A 1000kg chromium spaceship wrapped in 300 copper windings of resistance 80Ω was connected to an adjustable power source and accelerated out of Earth geosynchronous orbit through a series of radial magnetic fields of 3T to a speed of 0.65c. The maximum magnitude of voltage applied each time the spaceship passed through an iron ring was 2400V. You may assume all energy of induced eddy currents was transferred to the thermal energy of the chromium. The specific heat capacity of chromium is . A stationary observer observes the light emitted by the spaceship as it reaches a constant of 0.65c.
Use this stimulus to discuss and evaluate the significance of unifying our understandings of physics to apply the world around us with reference to past experiments and the law of conservation of energy.” (7 marks) (*mark to effort ratio is completely off as usual*) (*2 full pages of lines but you’re expected to also use all 4 pages of extra space cause why should NESA give you enough space*) (*criteria will also require full mechanical, orbital, electromagnetic, thermodynamic, relativistic and quantum calculations despite all indications that a written response was expected*) (*if you didn’t have at least 3 pros and 3 cons of some sort doesn’t matter what cause they don’t even know what you need to argue you will lose all marks cause they were all allocated to evaluation*) (*if you didn’t refer to at least 3 past experiments cause they gave plural but its physics so plural means 3 you get 0*) (*if you didn’t refer to conservation of energy enough that’s a 0 cause what are you doing*)

NESA's definition of a complex and difficult question is combining multiple surface level questions into one lmfao (take the 2024 or 2023 projectile motion question), this is entirely possible

 

[coolcat6778]

NESA's solutions are genuine dog shit. Why are they needlessly overcomplicating a legit surface level question?
My superior "band 6" response:
Vertical component:
v = u + at
v = 0, t = 3, g = −9.8 (vertical velocity zero at max height)
v = u + at => u = v − at => uy= 0 + (9.8)(3) = 29.4 m/s
Horizontal component:
s = ut
s = 130, t = 6
s = ut => u = s/t => ux = 130/6 m/s
Velocity vector:
u = root(ux^2 + uy^2) at angle tan(theta) = uy/ux
u = 36.521... m/s
theta = arctan(uy/ux) = 53.611 degrees

Initial velocity is 36.5 m/s, 53.611 degrees above horizontal

The use of the formula v^2 = u^2 + 2as is not only an unnecessary quadratic equation, it leads to a significant rounding error
_____________________________________________________________________________________________

This fucking sample answer deserves a 2, genuinely.

My response that actually got me 4/4 in the actual exam:
In model A, the maximum height reached will be much less compared to B.
This is because the force of mg acts according to 9.8 the whole journey rather than decreasing. This does more work according to W = ∫F ds, converting KE into PE. With model B, the height reached is substantial since gravity decreases at the inverse square from the center of Earth, thus area under Force versus displacement graph is lower, and less work changing KE into PE is done over the same displacement. Hence, it reaches a greater displacement.

My response doesn't contain useless unsuitable jargon as if this is English and garbage useless calculations and equations. It literally asked for a qualitative analysis lol

 

[C2H6O]

Like chem, my pred for last q:
“A 1000kg chromium spaceship wrapped in 300 copper windings of resistance 80Ω was connected to an adjustable power source and accelerated out of Earth geosynchronous orbit through a series of 200 radial magnetic fields of 3T produced by iron rings. The maximum magnitude of voltage applied each time the spaceship passed through an iron ring was 2400V. A stationary observer observes some light emitted by the spaceship as it reaches the end of the iron rings at a fraction of the speed of light.
You may assume all energy of induced eddy currents was transferred to the thermal energy of the chromium and that chromium behaves as an ideal black body. The specific heat capacity of chromium is .
Use this as a stimulus to discuss and evaluate the significance of unifying our understandings of physics to apply to the world around us with reference to past experiments and the law of conservation of energy.” (7 marks) (*mark to effort ratio is completely off as usual*) (*2 full pages of lines but you’re expected to also use all 4 pages of extra space cause why should NESA give you enough space*) (*criteria will also require full mechanical, orbital, electromagnetic, thermodynamic, relativistic and quantum calculations despite all indications that a written response was expected*) (*if you didn’t have at least 3 pros and 3 cons of some sort doesn’t matter what cause they don’t even know what you need to argue you will lose all marks cause they were all allocated to evaluation*) (*if you didn’t refer to at least 3 past experiments cause they gave plural but its physics so plural means 3 you get 0*) (*if you didn’t refer to conservation of energy enough that’s a 0 cause what are you doing*)

Sample answers out, memorise now cause phys is a memorisation subject apparently (chat cooked up):
The phenomenon of a 1000 kg chromium spaceship accelerating through a sequence of magnetic fields provides an extraordinary yet instructive example of how the unification of physical laws allows physicists to interpret complex events through coherent principles. By examining this process through the lenses of electromagnetism, mechanics, thermodynamics, and relativity, the scenario demonstrates the enduring significance of the law of conservation of energy and the interconnected nature of modern physics.

The acceleration of the spaceship as it passes through magnetic fields is best explained through Faraday’s law of electromagnetic induction, where the changing magnetic flux through the copper windings induces an electromotive force (EMF). This principle, experimentally demonstrated by Faraday in 1831, unified electricity and magnetism by establishing that motion and changing magnetic fields can produce current. The behaviour of the ship therefore exemplifies how electromagnetic laws extend beyond laboratory contexts, forming the basis of modern applications such as power generation and magnetic propulsion. The success of this model underscores the strength of unified physical frameworks in explaining seemingly diverse phenomena through common principles.

As electrical energy is converted into kinetic and thermal energy, Joule’s experiments on the mechanical equivalent of heat become directly relevant. His findings verified that energy cannot be created or destroyed, only transformed, a concept refined into the law of conservation of energy. Within this scenario, resistive heating from eddy currents transfers energy into the thermal store of the chromium hull, while the magnetic acceleration increases kinetic energy. The system’s predictability reflects the reliability of classical physics, yet this same determinism can become restrictive when neglecting non-classical effects such as radiation losses or quantum interactions. This highlights the dual nature of unification: while it provides clarity and predictive power, it sometimes oversimplifies complex realities.

As the spaceship’s velocity approaches a significant fraction of the speed of light, Einstein’s theory of special relativity extends the conservation principle to account for mass–energy equivalence (E = mc²). Relativistic effects such as time dilation, length contraction, and the Doppler shift of emitted light ensure that energy conservation remains valid across all reference frames. This seamless transition from classical to relativistic physics exemplifies the strength of unified models they adapt rather than collapse when confronted with new evidence. However, relativity’s abstract nature and mathematical complexity illustrate that greater unification often comes at the cost of accessibility and simplicity.

Ultimately, the chromium spaceship’s journey symbolises how the unification of physical understanding allows physicists to describe phenomena across vastly different domains using consistent laws. From Faraday’s discovery of induction to Einstein’s relativistic synthesis, each advancement represents not replacement but integration, reinforcing the coherence of the physical universe. The continued pursuit of unification, from thermodynamics to quantum mechanics, reflects physics’ central aim: to construct an internally consistent and universally applicable framework that both explains and evaluates the world around us.


Ofc it’s completely useless compared to what was expected of us and doesn’t even address half of the things mentioned in the scenario which you are expected to.

 

[v.tex]

Do we need to remember the entire chemical process for the CNO and PP chain, or can we just describe and state their net equations?

 

[v.tex]

Whats the bet its gonna be like one easy math question and the rest insane theory knowledge

 

[C2H6O]

Do we need to remember the entire chemical process for the CNO and PP chain, or can we just describe and state their net equations?

from my understanding net reaction is sufficient, but i would personally recommend knowing the pp chain at least, cno can also be memorised by starting with C-12, and remembering the sequence +proton, beta+ decay, +proton, + proton, beta+ decay, +proton (this is the 4th proton), get alpha particle and we're back at C-12. the transmutations of C-12 can be figured out from there.
for cno i think its more important to be able to describe well than memorise, cause its very unlikely to be needed, its more a thing of increasing your understanding

 

[C2H6O]

from my understanding net reaction is sufficient, but i would personally recommend knowing the pp chain at least, cno can also be memorised by starting with C-12, and remembering the sequence +proton, beta+ decay, +proton, + proton, beta+ decay, +proton (this is the 4th proton), get alpha particle and we're back at C-12. the transmutations of C-12 can be figured out from there.
for cno i think its more important to be able to describe well than memorise, cause its very unlikely to be needed, its more a thing of increasing your understanding

maybe a bit of a niche reference but i memorise it as 1 cycle is 1 bar of rhythm from "we will rock you". stomp is a fusion of a proton, and clap is a beta decay, and last step is final proton to unlock the alpha particle

 

[Trial&Error]

What exactly do we need to know about the balmer series? I don't really understand it if I'm being honest

 

[cheesynooby]

What exactly do we need to know about the balmer series? I don't really understand it if I'm being honest

mainly just how it relates to emission spectra for hydrogen like how the emission lines are from electrons relaxing from higher energy levels to n = 2
and how that can be related to bohr's model