A) 1 m/s
B) 2 m/s
C) 3 m/s
D) 4m/s
Correct Answer: A
Solution :
\[\tan {{45}^{o}}=\frac{r}{h}\Rightarrow \,h=r\] \[V=\frac{1}{3}\pi {{r}^{2}}\cdot \,r=\frac{1}{3}\pi {{r}^{3}}\] \[\Rightarrow \] \[\frac{dV}{dt}=\pi {{r}^{2}}\frac{dr}{dt}\] \[\Rightarrow \] \[\frac{dr}{dt}=\frac{2}{\pi \cdot 4}=\frac{1}{2\pi }\] \[\Rightarrow \] \[2\pi \frac{dr}{dt}=1\,m/\sec \]You need to login to perform this action.
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