a building is in the form of a right circular cylinder surmounted by a hemisphere both having same radii. the base diameter= 2/3 of total height of the building. find the height of the building if it contains 67 1/21 m3 AIR
Let h be the height of cylinder and r be the common base radii of cylinder and hemisphere and H be total height of building.
Diameter of dome = 2r
6r = 2h + 2r
4r = 2h
⇒h = 2r
According to given condition,
Volume of air inside the building = Volume of cylinder + Volume of hemisphere
r 3 = 8
⇒ r 3 = (2)3
⇒ r = 2 cm
∴ h = 2r
= 2 × 2 = 4 cm
Hence height of building = H = h + r
= 4 + 2 = 6 cm