Answer:
[tex]\dfrac{dV}{dt}=502.65\ mm^3/s[/tex]
Step-by-step explanation:
The volume of a sphere is given by :
[tex]V=\dfrac{4}{3}\pi r^3[/tex]
The rate of change of volume means,
[tex]\dfrac{dV}{dt}=\dfrac{d}{dt}(\dfrac{4}{3}\pi r^3)\\\\\dfrac{dV}{dt}=\dfrac{4}{3}\pi \times 3r\times \dfrac{dr}{dt}[/tex]
We have, [tex]\dfrac{dr}{dt}=2\ mm/s\ and\ r=40\ mm[/tex]
So,
[tex]\dfrac{dV}{dt}=\dfrac{4}{3}\pi \times 3\times 20\times 2\\\\=502.65\ mm^3/s[/tex]
So, the volume is increasing at the rate of [tex]502.65\ mm^3/s[/tex].
