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  1. alcalder

    selective schools for my sister? help me

    As a Mum of a boy eligible for Selective High School, this is a question I have been considering long and hard. It comes down to finding out all you can about the school: - reputation wise from current students, recent ex-students and parents of current students - by visiting and then asking...
  2. alcalder

    Does anyone know an experiment to measure the value for gravity's acceleration???

    The pendulum experiment is also the one in the syllabus.
  3. alcalder

    Electrical Circuits

    In that case, I'm not quite sure what it is you want to know. The "brushes" brush against the turning ring (commutator) and therefore complete the circuit and bring the current to the motor coil (or away from the generator coil). It is the coil's momentum that gets the brushes over the Split...
  4. alcalder

    Electrical Circuits

    If the wire held a current that was VERY VERY BIG and the wire was held vertical, then you would see the four compass needles circle around the wire. Using the right hand grip rule, hold the wire with your thumb in direction of the current (well, don't actually hold a wire with a VERY VERY BIG...
  5. alcalder

    Electrical Circuits

    A generator is making electricity, so the electrons are being given energy and so they flow from the positive to the negative side of the generator. (Hence current flows from negative to positive because it is essentially INSIDE the battery or power source.) A motor is using electricity, so the...
  6. alcalder

    Electrical Circuits

    Indeed you will, but never lose sight of the fact that Physics is a very integrated subject. You will use ideas and concepts across multiple topics. This is important when you decide on which equation to use. You may be studying ideas to implementation but may need to use an equation from...
  7. alcalder

    Essay Questions

    Past HSC Papers and marking notes can be found here: http://www.boardofstudies.nsw.edu.au/hsc_exams/index.html So, the 2004 HSC - German Continuers: Question 12 (6 marks) Answer ONE of the following questions. Write 100–150 words in GERMAN. (a) Write a letter to your German penfriend...
  8. alcalder

    How do we make soap?

    You need a good bit of lard to start with. Hence the reason they killed whale for their blubber - to make soap. Check out Wikipedia: http://en.wikipedia.org/wiki/Soap (someone has done something to some of the text, but the important bit is OK) Also look up saponification on Wikipedia and...
  9. alcalder

    Electrical Circuits

    In some ways it does encompass semi-conductors (and you now have aheads up on that) but it can also be said for electric circuits and metallic conductors. Those "free electrons" are not exactly free, they are valence electrons which are just easily knocked into the conduction band with the...
  10. alcalder

    Help: Circular motion at constant angular velocity

    OK here is a simple explanation. We know everything will go in a straight line with a constant speed if not acted upon by a force. Now, think about a body orbiting the Earth. What forces are on it? Only one, gravity. That acts directly between the object in orbit and the Earth. This force is...
  11. alcalder

    Electrical Circuits

    Conventional Current flow is from the positive terminal to the negative terminal in a circuit. However, current flow is actually due to electrons from the atoms flowing from the negative terminal to the positive terminal (in the opposite direction to conventional current. An unfortunate...
  12. alcalder

    Ohms Law Shortcut

    Just remember, it is a VIRy important equation. :)) I crack myself up.
  13. alcalder

    validty, realibilty

    Here we go, a good site about it: http://webs.mn.catholic.edu.au/physics/emery/accuracy.htm
  14. alcalder

    Please help me!! on satellites

    ;) Always try Wikipedia first. They have info AND great links at the bottom of the page to other sites. http://en.wikipedia.org/wiki/Satellite_television Hope this helps some.
  15. alcalder

    Inevitable Boredom

    Dear me. *rolls eyes* Now when I finished my HSC I was Drama Captain Prefect and had a whole production to get on the stage by mid-December. That kind of kept me busy. I used to have a 100 things to do list that I wrote out for a friend who similarly found herself at a loose end. Sorry, it's...
  16. alcalder

    Projectile Motion-help

    It's not a lot of calculus and the integrals are really really simple ones ;) But, hey, Ext 1 is all about Calculus, isn't it :D ? Ah the joys of calculus.:rofl:
  17. alcalder

    Determining Anode from Cathode

    Cathode rays (which are moving electrons) come from the Cathode and pass to the Anode (I know, that's Physics, but let me get to my point :D). THUS the cathode is the negative electrode and the anode is the positive electrode. This is OUTSIDE THE POWER SOURCE. The Cathode will be connected to...
  18. alcalder

    German Pop

    Actually Nena had a great album back in the late 1980's. "99 Luftballon" was on that album along with a heap of other great hits - "Leuchtturm" comes to mind. Herbert Grönemeyer is great too. When I studied German we studied songs and his were fantastic. My young son is rather partial to...
  19. alcalder

    Projectile Motion-help

    OK to do it the Ext 1 way, first take the initial velocity v at an angle θ to the horizontal and resolve it into vertical (y-direction) and horizontal (x-direction) components. INTIAL CONDITIONS at t=0 uy = vsinθ ux = vcosθ If you start on the horizontal, then at t=0, x=0 AND y=0 If you start...
  20. alcalder

    contribution of development of space exploration

    If you wanted to choose someone who has contributed to space exploration in a MAJOR MAJOR way in many different ways, then von Braun is perfect. HOWEVER, my personal preference is always to choose the little guy whose contribution seems, at first, so small and insignificant but it was...
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