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The breaking stress of the wire is $3.5\times 10^6 \,N/m^2$. It is observed that the minimum cross-sectional area of the wire so that it does not break is $18.67 \,cm^2$. Now I need to find out if the observation is right or not.

At first, I have calculated the acceleration of the blocks. It is $3.267\, m/s^2$. I don't whether it is useful or not in this regard.

We now that, $\displaystyle\text{Stress}= \frac{F}{\text{Area}}\,\text{or}\,\text{Area}=\frac{F}{\text{Stress}}$. I think I can get the area with this equation. Am I right?

How can I calculate $F$ here? Is it $5g+ 10g$? Or what? Please help me. Thanks.


Calculate tension ($F$) in the string. So $$ A_{min}=\frac{F}{\text{(Stress)}_{max}}.$$

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  • $\begingroup$ Thank you for your answer, @Doubtnut. I am having problem in calculating the F. Is it 5g+10g? Or what? Please help. $\endgroup$ – Mahfuz Saim Jun 16 at 4:50
  • $\begingroup$ That you have to calculate. We don't provide direct solution on this site. BTW, it is not? $\endgroup$ – SarGe Jun 16 at 4:55
  • $\begingroup$ Then is it (m1+m2)*(g-a)? I think it may work. What do you think? $\endgroup$ – Mahfuz Saim Jun 16 at 4:58
  • $\begingroup$ This may help you. $\endgroup$ – SarGe Jun 16 at 5:01
  • $\begingroup$ So, what I have understood from the video is F will be equals to 2M1M2g/(M1+M2). Am I right, @Doubtnut? Please answer. $\endgroup$ – Mahfuz Saim Jun 16 at 5:40

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