The radii of the internal and external surfaces of a hollow spherical shell are 3 cm and 5 cm respectively.  If it is melted and recast into a solid cylinder of height 8/3 cm, find the diameter of the cylinder

Asked by jaychandran1967 | 30th Mar, 2017, 05:00: PM

Expert Answer:

Volume of the sphere = 4/3 π (R3 - r3)
= (4/3) (22/7) (53 - 33)
= (4/3) (22/7) (98)
= 410.67 cm3

Height of the cylinder formed = 8/3 cm
Let the radius of the cylinder be 'r' cm

Volume of the cylinder = πr2h
Volume of the cylinder = 22/7 x r2 x 8/3
                        410.67 = 22/7 x r2 x 8/3 
r= 49
r = 7 cm (approximately)

∴ Diameter of the cylinder = 2 x 7 =14 cm

Answered by Rebecca Fernandes | 31st Mar, 2017, 09:36: AM