Recent content by songoku

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

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...

Thank you very much anuttarasammyak

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

Thank you very much .Scott, haruspex, Gavran

For this case, is this also called induction?

If that is the case, there is discharging between the clouds so can I say there is induction between clouds? Thanks

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...

I understand. Thank you very much Gavran

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

Thank you very much for all the explanations Lnewqban, Gavran, haruspex, Steve4Physics

How can we get this information from the question?

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

I treat this question as two cases of Doppler effect. (1) When the sound wave travels from bat to moth Speed of sound = 222 x 1.5 = 333 m/s Frequency received by moth: $$f_1=\frac{333+v}{333}\times 222$$ (2) When the sound wave is reflected from moth back to bat Frequency received by bat...

Thank you very much for all the help and explanation kuruman, jbriggs444, Lnewqban, Herman Trivilino, Gavran, haruspex