Question

29. a) The diameter of the internal and external surfaces of a hollow
hemispherical shell are 6 cm. and 12 cm. respectively. It is melted and
recast into a solid cylinder of height 2 cm. Find the radius of the
cylinder.​

Answer 1

Answer:

Step-by-step explanation

When the sphere is melted and recast the total volume remains constant.

volume of hollow sphere =$\frac{4}{3} \pi (x^{3} -y^{3} )$

where x is the outer radius and y is the inner radius

∴ volume of the sphere is 2016π

volume of cylinder = $\pi r^{2} 2$

$\pi r^{2} 2$ = 2016π

r² = 1008

r = 12√7 cm