Water is leaking out of an inverted conical tank at a rate of 10,000 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 6 m and the diameter at the top is 4 m. If the water level is rising at a rate of 20 cm/min when the height of the water is 2 m, find the rate at which water is being pumped into the tank. (Round your answer to the nearest integer.)

Respuesta :

Answer:

Water is being pumped at a rate of [tex]x=9972.07cm^{3}/min[/tex]

Explanation:

We have volume of right circular cone is given by

[tex]V=\frac{1}{3}\pi r^{2}h[/tex]

Differentiating with respect to time we get

[tex]V=\frac{1}{3}\pi r^{2}h\\\\\frac{dV}{dt}=\frac{\pi }{3}(2rh\times \frac{dr}{dt}+\pi r^{2}\frac{dh}{dt})[/tex]

Now let the rate at which water is entering the conical vessel be [tex]xcm^{3}/min[/tex]

The cumulative change in volume is given by [tex](10000-x)[/tex]

By similar angle criterion of the triangle we have

[tex]\frac{2}{6}=\frac{r(h)}{h}\\\\\therefore r(h)=\frac{h}{3}[/tex]

[tex]\frac{dr(h)}{dt}=\frac{dh(t)}{3dt}[/tex]

Using all the above results we in the above equation we have

[tex]10000+x=\frac{\pi }{3}(\frac{2^{3}\times 20}{9}+\frac{4\times 20}{9})[/tex]

Solving for x we get

[tex]x=9972.07cm^{3}/min[/tex]

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