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  1. wizzkids

    standard solution q

    ANSWER: no effect on the concentration of the standard solution. The two critical parameters for making a standard solution are you must have an accurate number of moles inside the flask, and the volume must be made up to the scribe mark with distilled (or deionised) water. The temperature of...
  2. wizzkids

    question about resonance

    Sound resonance in tubes works like this: Air molecules can oscillate as a longitudinal wave up and down a tube. An open end is always an antinode, because the air molecules are free to oscillate without any restraint. A closed end is always a node, because when the pressure wave arrives at the...
  3. wizzkids

    Does anyone have resources for photoelectric depth study?

    Now I know it is a bit hard for high school students to obtain apparatus for a first-hand investigation. Your research can be a first-hand investigation or a second-hand investigation of other people's data; they are both valid for depth studies. You could investigate modern devices that exploit...
  4. wizzkids

    Does anyone have resources for photoelectric depth study?

    To gain a solid understanding of the evidence for the photoelectric effect, I recommend students watch this video. It's an oldie but a goodie. Don't worry about the wooden Physics professor who does the demonstration; he knows his stuff, that's all that matters.
  5. wizzkids

    Spectroscopy

    Yes there is. Go to https://pubchem.ncbi.nlm.nih.gov/ The Published Chemistry Database of the National Library of Medicine. From there you can branch to all the other chemical databases.
  6. wizzkids

    Interference Questions

    That is correct. The answer is an irrational number, but in an exam you have to choose the closest option which is (C).
  7. wizzkids

    A question about the justification behind the solution of a problem.

    Actually in the solution it would have been quicker to state the law of triangles, sum of the interior angles must be 180o and therefore the gradient of the line CB must be -1.
  8. wizzkids

    physics problem

    The free-body diagram has three vectors as shown below.
  9. wizzkids

    Interference Questions

    This is the Double Slit Experiment. Go look up the Physics formula sheet and you will find a formula that links the positions of constructive interference in the interference pattern with the wavelength of light and the spacing d between the slits. Then you just have to interpret the information...
  10. wizzkids

    Hypothesis?

    Yes, the hypothesis needs to be in there, otherwise what are you investigating? Your hypothesis creates the inquiry question, and your hypothesis must be referred to in your closing remarks to determine if you achieved what you set out to do. Spoiler Alert: drag force is not proportional to...
  11. wizzkids

    Why is not A?

    I chose my point of reference as the top of the cliff, so distances are measured from the top of the cliff.
  12. wizzkids

    Why is not A?

    @kkk579 The answer given in the paper is wrong, btw. There is nothing fundamentally wrong with your calculation, but there is no need to include the mass of the block. All objects fall at the same rate regardless of their mass. You can use the standard equations for uniformly accelerated motion.
  13. wizzkids

    Why is not A?

    Yes, you could do the calculation that way. If the object has half it's final velocity then it has a quarter of its final kinetic energy, and therefore it has lost a quarter of its gravitational potential energy, so it has fallen 1/4 x 50 metres, and it is 37.5 metres above the ground.
  14. wizzkids

    Why is not A?

    @kkk579 In question 6 (c) you performed a calculation based on energy. The correct way to calculate the height is to use v2 =u2 +2as Make v = 15.65 m/s, let u =0 and rearranging terms we can say S = 15.652 / 2 x 9.8 and the answer is 12.49 m
  15. wizzkids

    Why is not A?

    Question 15 (a) is also badly worded. I think what the examiner meant to say was, "Draw the force-vector diagram at the point Y." If you answer the question literally, the free-body diagram for the mass A is trivial, as @kkk579 has shown, although quantifying the forces is not quite so trivial...
  16. wizzkids

    Why is not A?

    There is no correct answer. All the options are false. The best way to analyse this force-time graph is to recognise that the area under the force-time graph is equal to the Impulse, which is also equal to the Change of Momentum. Break the graph into three regular shapes, a triangle, a...
  17. wizzkids

    How to find the direction of an induced current when the direction of movement is unknown?

    Where does it say that the loop is moving? The loop isn't moving. You need to practice reading exam questions carefully and answering exactly the question you are given, not the question that you have memorised.
  18. wizzkids

    historical film investigation

    You could investigate the film "Lawrence of Arabia" directed by David Lean. You could investigate the works of Leni Riefenstahl.
  19. wizzkids

    Provisional Accreditation

    Yes, almost certainly if your degree is from a respected Australian University you won't have a problem. Accreditation is all about the planning and execution by the University. It's not you that needs to be accredited. It's the faculty, their curriculum, their assessment practices and their...
  20. wizzkids

    pulley question

    Geez, this is a wacko question. Where did you get it? One way to solve the problem is to treat it as a lumped system. Determine the total moving mass of the system, determine the net force on the system, and from that work out the acceleration of the whole system. Then knowing the acceleration...
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