Sunday

December 21, 2014

December 21, 2014

Posted by **yohannes** on Friday, January 4, 2013 at 3:09am.

- physics -
**drwls**, Friday, January 4, 2013 at 5:56amYou seem to have left out some words in your question, such as:

The radius of sphere IS INCREASING at the rate of 4cm per second.

Surface area is

A= 4*pi*R^2

The rate of increase of surface area is

dA/dt = 8*pi*R*(dR/dt)

Plug in 6 cm for R, and dR/dt = 4 cm/s, and compute

- physics -
**Elena**, Friday, January 4, 2013 at 6:01amR=4t (cm)

6=4t

t=1.5 s.

A=4πR²=4π(4t)²=

=64πt²=64π(1.5)²=452.4 cm²

- physics -
**Elena**, Friday, January 4, 2013 at 6:06amdA/dt = 64πt²=128 πt=128 π•1.5=603.2 cm²/s

**Answer this Question**

**Related Questions**

mathematics - What is the solution for this? The surface area of a sphere varies...

calculus *improper integrals* - A hole of a radius of 1cm is pierced in a sphere...

Calculus (Parts A and B done, just help with C) - The radius, r, of a sphere is ...

calculus - A hole of a radius of 1cm is pierced in a sphere of a 4cm radius. ...

geometry - The radius R of a sphere is 5.6cm. Calculate the sphere's surface ...

Geometry/Algebra/Calculus - Why isn't the surface area of a sphere with radius r...

math - direct variation the surface area of a sphere varies directly as the ...

Physics - Sphere 1 has surface area A1 and volume V1, and sphere 2 has surface ...

Calculus Homework - You are blowing air into a spherical balloon at a rate of 7...

astrophysics - 1) Every second the Sun outputs 3.90* 10^26 Joules of energy. ...