Advertisements
Advertisements
प्रश्न
The total surface area of a hollow metal cylinder, open at both ends of external radius 8 cm and height 10 cm is 338π cm2. Taking r to be inner radius, write down an equation in r and use it to state the thickness of the metal in the cylinder.
उत्तर
Surface area of the hollow cylinder = 338π cm2
2π(8)10 + 2π(r)10 + 2[ π(8)2 - π(r)2] = 338 π
⇒ 160 + 20r + 2(64 - r2) = 338
⇒ - 2r2 + 20r - 50 = 0
⇒ r2 - 10r + 25 = 0
⇒ (r - 5)2 = 0
⇒ r = 5
∴ Thickness of the metal in the cylinder = 8 - r = 8 - 5 = 3 cm.
APPEARS IN
संबंधित प्रश्न
Curved surface area of a right circular cylinder is 4.4 m2. If the radius of the base of the cylinder is 0.7 m, find its height.
`["Assume "pi=22/7]`
A cylindrical container with diameter of base 56 cm contains sufficient water to submerge a rectangular solid of iron with dimensions 32 cm × 22 cm × 14 cm. Find the rise in the level of the water when the solid is completely submerged.
What length of a solid cylinder 2 cm in diameter must be taken to recast into a hollow cylinder of length 16 cm, external diameter 20 cm and thickness 2.5 mm?
A rectangular sheet of paper, 44 cm × 20 cm, is rolled along its length of form a cylinder. Find the volume of the cylinder so formed.
From a tap of inner radius 0.75 cm, water flows at the rate of 7 m per second. Find the volume in litres of water delivered by the pipe in one hour.
The volume of a solid cylinder is 7700cm3. Find its height and total surface area if the diameter of its base is 35cm.
The radius of the base of a right circular cylinder is doubled and the height is halved. What is the ratio of volume of the new cylinder to that of the original cylinder?
In the example given below, the radius of the base of a cylinder and its height is given. Then find the curved surface area and total surface area.
r = 1.4 cm, h = 2.1 cm
In the example given below, the radius of the base of a cylinder and its height is given. Then find the curved surface area and total surface area.
r = 4.2 cm, h = 14 cm
