Physics
posted by Amy .
Two spheres are cut from a certain uniform rock.One has radius 4.50 cm.The mass of the other is five times greater. Find its radius.

Since the rock is of uniform density, the ratio of the masses is the same as the ratio of the volumes.
V = 4/3 pi r^3
So, 5 * 4/3 pi r^3 = 4/3 pi * 5 r^3 = 4/3 pi * (cbrt(5)*r)^3
So, the new radius is cube root 5 times the old one. 
the Answer is not 4/3pi times the cubed root of 5 times the r^3...it is just cubed root 5 times the radius of 4.5