A) 2s
B) 4s
C) 8s
D) 10 s
Correct Answer: B
Solution :
When a body is revolving in circular motion it is acted upon by a centripetal force directed towards the centre. Water will not fall if weight is balanced by centripetal force. Therefore, \[mg=\frac{m{{v}^{2}}}{r}\] \[\Rightarrow \] \[{{v}^{2}}=rg\] ?(i) Circumference of a circle is \[2\pi r.\] Time for a revolution\[=\frac{2\pi r}{v}\] Putting the value of \[v\] from Eq. (i), we get \[T=\frac{2\pi r}{\sqrt{gr}}=2\pi \sqrt{\frac{r}{g}}\] Given, \[r=4m,g=9.8\,m/{{s}^{2}}\] \[\therefore \] \[T=2\pi \sqrt{\frac{4}{9.8}}T=\frac{4\pi }{\sqrt{9.8}}=4s\]You need to login to perform this action.
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