A cylindrical vessel of diameter 14 cm and height 42 cm is fixed symmetrically inside a similar vessel of diameter 16 cm and height 42 cm. The total space between two vessels is filled with cork dust for heat insulation purposes. How many cubic centimetres of cork dust will be required?
(Ans:1980 cu.cm)
Ans: volume of cork dust required = π R2 h - π r2 h
= π 42 [ 64 - 49]
= 1980 cm3