CHAPTER 20 CYLINDER CONES CONCISE MATHEMATICS SELINA SOLUTIONS EX 20 B
Q11. Find the area of the canvas required to make a conical tent 14 m high and 96 m in diameter. Given that : (i) 20% of the canvas is used in folds and stitching. (ii) canvas used in folds and stitching is 20% of the curved surface area of the tent.
Q10. A vessel, in the form of an inverted cone, is filled with water to the brim. Its height is 20 cm and diameter is 16.8 cm. Two equal solid cones are dropped in it so that they are fully submerged. As a result, one-third of the water in the original cone overflows. What is the volume of each of the solid cones submerged ?
Q8. The ratio of the base area and the curved surface area of a conical tent is 40 : 41. If its height is 18 m, find the air capacity of the tent in terms of π.
EX20A Q3. A cylinder of circumference 8 cm and length 21 cm rolls without sliding for 41 seconds at the rate of 9 complete rounds per second. Find (i) the distance traveled by the cylinder in 4-1/2 seconds, and (ii) the area covered by the cylinder in 4 seconds.
EX20A Q8. A cylindrical container with diameter of base 42 cm contains sufficient water to submerge a rectangular solid of iron with dimensions 22 cm x 14 cm x 10.5 cm. Find the rise in the level of the water when the solid is sub-merged.
EX20A Q14. Find the minimum length in cm and correct to nearest whole number of the thin metal sheet required to make a hollow and closed cylindrical box of diameter 20 cm and height 35 cm. Given that the width of the metal sheet is I m. Also, find the cost of the sheet at the rate of 56 per m. Find the area of metal sheet required, if 10% of it is wasted in cutting, overlapping, etc.
EX20A Q10. Find the total surface area of an open pipe of length 50 cm, external diameter 20 cm and internal diameter 6 cm.
EX20A Q11. The height and the radius of the base of a cylinder are in the ratio 3: 1. If its volume is 1029 cm^3; find its total surface area.
EX20A Q12. The radius of a solid right circular cylinder increases by 20% and its height decreases by 20%. Find the percentage change in its volume.
EX20A Q15. 3080 cm^3 of water is required to fill a cylindrical vessel completely and 2310 cm^3 of water is required to fill it upto 5 cm below the top.
Find : (i) radius of the vessel. (ii) height of the vessel. (iii) wetted surface area of the vessel when it is half-filled with water.
EX20A Q18. A circular tank of diameter 2 m is dug and the earth removed is spread uniformly all around the tank to form an embankment 2 m in width and 1.6 m in height. Find the depth of the circular tank.
EX20A Q21. The sum of the height and the radius of a solid cylinder is 35 cm and its total surface area is cylinder is 35 cm and its total surface area is 3080 cm^2; find the volume of the cylinder.
EX20A Q22. The total surface area of a solid cylinder is 616 cm^2. If the ratio between its curved surface area and total surface area is 1:2; find the volume of the cylinder.
EX20A Q23. A cylindrical vessel of height 24 cm and diameter 40 cm is full of water. Find the exact number of small cylindrical bottles, each of height 10 cm and diameter 8 cm, which can be filled with this water.
EX20A Q24. Two solid cylinders, one with diameter 60 cm and height 30 cm and the other with radius 30 cm and height 60 cm, are melted and masted into a third solid cylinder of height 10 cm. Find the diameter of the cylinder formed.
EX20A Q25. The total surface area of a hollow cylinder, which is open from both the sides, is 3575 cm^2; area of its base ring is 357.5 cm^2 and its height is 14 cm. Find the thickness of the cylinder.
EX20A Q28. A closed cylindrical tank, made of thin iron- sheet, has diameter = 8.4 m and height 54 m. How much metal sheet, to the nearest m^2, is used in making this tank, if 1/15 of the sheet actually used was wasted in making the tank ?
In this lecture we learn standard equation of line, how to plot a line,
what are X and Y intercepts, Various shapes in which line equatin can be
written, properties of points that lie on a line, slope and inclination
of a line, properties of rhombus and square, slopes of parallel and
prependicular lines, slopes of corrdinate axis, 4 types of equation of
line, lines making equal angles with coordinate axis, collinear and
concurrent points.
