A) \[AE\frac{R}{r}\]
B) \[AE\left( \frac{R-r}{r} \right)\]
C) \[\frac{E}{A}\left( \frac{R-r}{A} \right)\]
D) \[\frac{Er}{Ar}\]
Correct Answer: B
Solution :
[b] Initial length (circumference) of the ring \[=2\pi r\] Final length (circumference) of the ring \[=2\pi R\] Change in length \[=2\pi R-2\pi r\] \[Strain=\frac{2\pi (R-r)}{2\pi r}=\frac{R-r}{r}\] Young?s modulus \[E=\frac{F/A}{l/L}=\frac{F/A}{(R-r)/r}\] \[\therefore \,\,F=AE\left( \frac{R-r}{r} \right)\]You need to login to perform this action.
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