A conical paper cup is 10 cm tall with a radius of 10 cm. The cup is being filled with water so that the water level rises at a rate of 2 cm/sec. At what rate is water being poured into the cup when the water level is 8 cm?

Respuesta :

Answer:

Water is being pored in the cone with the rate of 401.92 cm³ per second.

Step-by-step explanation:

There is a cone having height h = 10 cm and radius r = 10 cm

That means h = r

Rate of change of water level [tex]\frac{dh}{dt}=2[/tex] cm per second

Since volume of a cone is represented by the formula,

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

Now we have to find the value of [tex]\frac{dV}{dt}[/tex].

[tex]\frac{dV}{dt}=\frac{d}{dt}(\frac{1}{3}\pi r^{2}h)[/tex]

Since r = h

[tex]\frac{dV}{dt}=\frac{d}{dt}(\frac{1}{3}\pi h^{3} )[/tex]

[tex]\frac{dV}{dt}=\frac{3}{3}\pi h^{2}.\frac{dh}{dt}[/tex]

For h = 8 cm and [tex]\frac{dh}{dt}=2[/tex] cm per second.

[tex]\frac{dV}{dt}=\frac{3}{3}\pi (8)^{2}\times (2)[/tex]

[tex]\frac{dV}{dt}=128\pi[/tex] = 401.92 cubic cm per second

Therefore, water is being pored with the rate of 401.92 cm³ per sec.

Ver imagen eudora

At the rate of  [tex]128\pi\ cm^{3}/sec[/tex] water being poured into the cup when the water level is [tex]8[/tex] cm

The above figure shows the variables

Radius of conical cup([tex]R[/tex])[tex]=10[/tex] cm

Height of the conical cup () cm

Height of water level in cup at time , cm

Radius of water at time [tex]t[/tex] [tex]=r[/tex] cm

Volume of water at time [tex]t[/tex][tex]=V^{3}[/tex]

[tex]\dfrac{\partial h}{\partial t}=2m/sec[/tex]

Triangle [tex]ABC[/tex] is similar to triangle [tex]PBQ[/tex]

[tex]\frac{r}{h} = \frac{r}{h}[/tex]

[tex]\frac{r}{h} = \frac{10}{10}[/tex]

[tex]r=h\\r=8[/tex]

find [tex]\dfrac{dV}{dt}[/tex] which is rate of water being poured in cup.

The volume of a [tex]PBQ[/tex] cone is,

[tex]\begin{aligned}Volume&= Area\;of\;circle \times h\\&=\pi r^2 h\end{aligned}[/tex]

           

Differentiate with respect to [tex]t[/tex] we get:

[tex]\dfrac{dV}{dt} = \pi r^{2}\frac{dh}{dt}[/tex]

[tex]\dfrac{dV}{dt} = \pi (8)^{2}\times 2[/tex]

Therefore , [tex]\dfrac{dV}{dt}=128\pi\ cm^{3}/sec[/tex]

Learn more about Volume related concepts here:

https://brainly.com/question/13338592?referrer=searchResults

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