Advertisements
Advertisements
प्रश्न
A cylinder of circumference 8 cm and length 21 cm rolls without sliding for `4 1/2` seconds at the rate of 9 complete rounds per second. Find the area covered by the cylinder in `4 1/2` seconds.
उत्तर
Circumference of cylinder = 8 cm
Therefore, radius = `c/(2pi) = (8 xx 7)/(2 xx 22) = 14/11 cm`
Length of the cylinder (h) = 21 cm
Curverd surface area = 2πrh
= `2 xx 22/7 xx 14/11 xx 21`
= 168 cm2
Area covered in one revolution = 168 cm2
Area covered in 9 revolution = 168 cm2 × 9 = 1512 cm2
Therefore, area covered in 1 second = 1512 cm2
Hence, area covered in `4 1/2` seconds = `1512 cm^2 xx 9/2`
= 6804 cm2
APPEARS IN
संबंधित प्रश्न
A soft drink is available in two packs − (i) a tin can with a rectangular base of length 5 cm and width 4 cm, having a height of 15 cm and (ii) a plastic cylinder with circular base of diameter 7 cm and height 10 cm. Which container has greater capacity and by how much?
`["Assume "pi=22/7]`
A vessel is a hollow cylinder fitted with a hemispherical bottom of the same base. The depth of the cylindrical part is `4 2/3` m and the diameter of hemisphere is 3.5 m. Calculate the capacity and the internal surface area of the vessel.
A cylindrical water tank of diameter 2.8 m and height 4.2 m is being fed by a pipe of diameter 7 cm through which water flows at the rate of 4 m s–1. Calculate, in minutes, the time it takes to fill the tank.
What length of solid cylinder 2 cm in diameter must be taken to recast into a hollow cylinder of external diameter 20 cm, 0.25 cm thick and 15 cm long?
A metal container in the form of a cylinder is surmounted by a hemisphere of the same radius. The internal height of the cylinder is 7 m and the internal radius is 3.5 m. Calculate: the internal volume of the container in m3.
Volume of a cylinder with radius h and height r is ______.
Two cylinders of equal volume have heights in the ratio 1 : 9. The ratio of their radii is ______.
How many cubic metres of earth must be dug to construct a well 7 m deep and of diameter 2.8 m?
Radius of a cylinder is r and the height is h. Find the change in the volume if the height is doubled.
Volume of a cylinder is 330 cm3. The volume of the cone having same radius and height as that of the given cylinder is:
