Air is pumped into a spherical balloon, so the balloon expands. The volume of a sphere of radius R is 4πR3/3. If the radius of the sphere after t seconds is 2t centimeters, at what rate is air being pumped in when t=4? (Hint: the rate air is pumped in equals the rate that the volume of the sphere increases).

Respuesta :

Answer:

So rate of pump after t =4 sec will be [tex]1607.68cm^3/sec[/tex]

Explanation:

We have given that volume of the sphere [tex]V=\frac{4}{3}\pi R^3[/tex]

It is given that at after t sec radius of the sphere is 2t cm

So volume of the sphere [tex]V=\frac{4}{3}\pi (2t)^3=\frac{32}{3}\pi t^3[/tex]

After differentiating [tex]\frac{dV}{dt}=32\pi t^2[/tex]

We have to find the rate of pump at t = 4 sec

So [tex]\frac{dV}{dt}[/tex] at t = 4 sec

[tex]\frac{dV}{dt}=32\times 3.14\times 4^2=1607.68cm^3/sec[/tex]

So rate of pump after t =4 sec will be [tex]1607.68cm^3/sec[/tex]