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  1. porcupinetree

    HSC 2016 MX2 Marathon (archive)

    Re: HSC 2016 4U Marathon Once it's been proven, it's been proven Ceebs finding a more elegant proof for the sake of it lmao
  2. porcupinetree

    HSC 2016 MX2 Marathon (archive)

    Re: HSC 2016 4U Marathon Thought there was something like that right under my nose.
  3. porcupinetree

    HSC 2016 MX2 Marathon (archive)

    Re: HSC 2016 4U Marathon
  4. porcupinetree

    Quick Q's

    I can confirm that Nailgun is correct - asking a more specific question is much more beneficial.
  5. porcupinetree

    Prelim Physics Thread

    The equation ΣF=ma (where ΣF and a are vector quantities pointing in the same direction), which is one way to write Newton's 2nd law, isn't as much derived from other equations/laws, rather, it provides a definition of net force - i.e. if an object is accelerating, then there is a net force...
  6. porcupinetree

    Quick Q's

    Coulomb's Law can be considered to be derived from Gauss' Law (which is essentially a law about electric flux), but in essence (at least at HSC level), Coulomb's Law is a fundamental law that exists because it successfully describes our experimental observations, rather than because it is...
  7. porcupinetree

    Quick Q's

    The constituents of atoms (ie nuclei & electrons) are charged; the interactions of these charges leads to electrostatic forces in accordance with Coulomb's Law. (ie like charges repel, opposites attract)
  8. porcupinetree

    Quick Q's

    Again, normal forces such as this occur because of electrostatic interactions on the atomic scale. The ball accelerates upwards as is described by Newton's 2nd Law F=ma (i.e. a force causes an acceleration in the direction of the force). Then, by Newton's third law, the ball will apply an equal...
  9. porcupinetree

    Quick Q's

    Specifically, the ball experiences a force when it comes into contact with the wall because of electrostatic interactions between the ball's atoms and the wall's atoms.
  10. porcupinetree

    Hard Questions

    \int \sqrt{tanx}\ dx $ Bonus question: prove that there are no three positive integers $a, b, c$ that can satisfy the equation $a^n + b^n = c^n$ for any integer n $>$ 2.$
  11. porcupinetree

    Quick Q's

    The Law of Conservation of Momentum is as follows: "The total momentum of a system is conserves if no external net force acts upon the system." In your example, it seems to me that you specify the ball as the system in question. If no external forces acted on the ball, then we would expect its...
  12. porcupinetree

    Question

    W = Fs = mg*h = 250kg * 9.8 ms^-2 * (1.6+0.45) = 5.0 x 10^3 J (2 sig. fig.)
  13. porcupinetree

    HSC 2016 Maths Marathon (archive)

    Re: HSC 2016 2U Marathon You're missing out tbh
  14. porcupinetree

    HSC 2016 MX2 Marathon (archive)

    Re: HSC 2016 4U Marathon $In typical BoS meet up style, KingOfActing and Ekman decide to demolish a HSP together. However, for some variety, instead of demolishing it in their usual fashion (i.e. by consumption), they decide to literally demolish it by projecting it vertically upwards through a...
  15. porcupinetree

    Hardest Questions In HSC maths?

    In the 1998 (I think?) 4U HSC there was a question to prove the AM-GM inequality which iirc only 4 people successfully answered according to the marker's notes. There was also a tricky proof for the irrationality of pi sometime in the early-mid '00s iirc
  16. porcupinetree

    Donald Trump

    Re: April Fools Pranks You obvs haven't met him irl LOL
  17. porcupinetree

    Should I do 4u?

    +1 to this. At least give 4U a try, if you hate it then you can always drop it (given that you've got enough units to do so). Not only is it worth it for the scaling, but it's a really interesting course too - you're bound to enjoy at least some of it. Plus doing 4U will develop your abilities...
  18. porcupinetree

    Does God exist?

    Trying to explain away someone's belief in God because it may or may not have evolved from context does nothing to disprove the existence of that particular God.
  19. porcupinetree

    Can I get a good ATAR?

    Yes, it is absolutely possible for you to get an ATAR above 70 - if you consistently put in effort to study throughout your whole HSC year, and can manage your time well (i.e. don't procrastinate too much), you can achieve an ATAR well above 70. For your combination of subjects, you'd need to be...
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