Question

Two spheres of the same density have a ratio of 4 to 9 in surface area. If the small sphere weighs 10kg, what does the other sphere weigh?

Answer 1

Surface Area = 4 * Pi * r2

A1 / A2 = r1 sq / r2 sq
4 / 9 = r1 sq / r2 sq
taking sq rt...
So r1 / r2 = 2/3

Volume of sphere = 4/3 * pi * r3
So for two spheres...

V1 / V2 = r1 cube / r2 cube = (2 / 3 ) power of cube = 8/ 27

Now, Density is same for both spheres, and density = Mass / Volume..

M1 / V1 = M2 / V2

Given, M1 = 10 Kg

so M2 = (10 * 27) / 8 = 33.75 Kg...

is that right answer ???

Answer 2

I'll find out tomorrow :S Hahaha Thanks

Answer 3

Method is definitely right, might be calculation error..

and , do not blame me, if something goes wrong.... :D

All the Best !!!!!