Recent content by songoku

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    Correct statement about size of wire to produce larger extension

    Thank you very much for all the help and explanation haruspex, wrobel, Herman Trivilino, 256bits, Steve4Physics, jbriggs444
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    Correct statement about size of wire to produce larger extension

    avoid making the assumption and use all the information provided. For this question, consideration about breaking stress was not in my head until I read your reply
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    Correct statement about size of wire to produce larger extension

    I see. I need to consider breaking stress What about the formula: Young Modulus = stress / strain? Does it work under large stress because I am thinking the breaking stress of both wire is the same so the strain on the second wire must be constant and can be achieved by using longer wire? Thanks
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    Correct statement about size of wire to produce larger extension

    The answer is (B) but I don't really understand why. Based on formula of Young Modulus: $$x=\frac{FL}{AE}$$ The second wire made of the same material so it means they have same Young Modulus. Larger extension means larger value of ##x## so to get larger value of ##x## we can increase ##F## and...
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    Correct statement about random process of radioactive decay

    The correct answer is (C) but I don't understand why (B) is wrong. Isn't (B) also the meaning of random process? I though (B) and (C) are both correct. Thanks
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    Which one is correct statement regarding lightning?

    Thank you very much .Scott, haruspex, Gavran
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    Which one is correct statement regarding lightning?

    For this case, is this also called induction?
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    Which one is correct statement regarding lightning?

    If that is the case, there is discharging between the clouds so can I say there is induction between clouds? Thanks
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    Which one is correct statement regarding lightning?

    My answer is (B) but the correct answer is (D). I don't understand why there is induction between clouds and ground. I thought there will only be separation of charges in ground (polarization) due to large negative charges in the clouds causing the ground below the clouds will be positively...
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    Is this biased or unbiased Method of Moments Estimator?

    I understand. Thank you very much Gavran
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    Is this biased or unbiased Method of Moments Estimator?

    (i) $$E(X)=\bar X$$ $$(-1)\left(\frac{\theta}{2}\right)+(1)\left(\frac{\theta}{2}\right)=\bar X$$ $$\bar X=0$$ Then: $$\text{Var} (X)=\bar {X^2}-(\bar X)^2$$ $$(1)\left(\frac{\theta}{2}\right)+(1)\left(\frac{\theta}{2}\right)=\bar {X^2} - 0$$ $$\theta = \frac{1}{n} \sum_{i=1}^{n} X_{i}^{2}$$...
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    Speed of moth related to Doppler Effect

    Thank you very much for all the explanations Lnewqban, Gavran, haruspex, Steve4Physics
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    Speed of moth related to Doppler Effect

    How can we get this information from the question?
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    Speed of moth related to Doppler Effect

    You mean both bat and moth will detect frequency of 230.3 kHz?