Description : A spherical ball is divided into two equal halves. If the curved surface area of each half is 56.57 cm?, find the volume of the spherical ball.11531/cylinder-radius-halved-and-height-doubled-then-find-volume-with-respect-original-volume -Maths 9th
Last Answer : since curved surface of half of the spherical ball = 56.57 cm2 ∴ 2πr2 = 56.57 ⇒ r2 = 56.57 / 2 × 3.14 = 9 ⇒ r = 3 cm Now, volume of spherical ball = 4 / 3 πr3 = 4 / 3 × 3.14 × 3 × 3 × 3 = 113.04 cm3
Description : The volume of cube is increasing at a rate of `9 cm^(3)//sec`. Find the rate of increase of its surface area when the side of the cube is 10 cm.
Last Answer : The volume of cube is increasing at a rate of `9 cm^(3)//sec`. Find the rate of increase of its surface area when the side of the cube is 10 cm.
Description : The surface of a spharical balloon is increase of its volume when its radius is 6 cm.
Last Answer : The surface of a spharical balloon is increase of its volume when its radius is 6 cm.
Description : The radius of a spherical balloon increases from 6 cm to 12 cm as air is being pumped into it. -Maths 9th
Last Answer : Surface area of a spherical balloon whose radius is 6 cm. = 4π × 6 × 6 cm2 Surface area of a spherical balloon whose radius is 12 cm. = 4π × 12 × 12 cm2 ∴ Ration of surface areas = 4π × 6 × 6 / 4π × 12 × 12 = 1 / 4 = 1 : 4
Description : The rate of increase of the radius of an air bubble is 0.5 cm/sec. Find the rate o fincrease of its volume when the radius of air bubble is 2 cm.
Last Answer : The rate of increase of the radius of an air bubble is 0.5 cm/sec. Find the rate o fincrease of its volume when the radius of air bubble is 2 cm.
Description : The radius of a spherical balloon increases from 7cm to 14cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases. -Maths 9th
Last Answer : Let r1 and r2 be the radii of spherical balloon and spherical balloon when air is pumped into it respectively. So r1 = 7cm r2 = 14 cm Now, Required ratio = (initial surface area)/(Surface area after pumping air into ... = (7/14)2 = (1/2)2 = ¼ Therefore, the ratio between the surface areas is 1:4.
Description : A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5cm. Find the outer curved surface of the bowl. -Maths 9th
Last Answer : Inner radius of hemispherical bowl = 5cm Thickness of the bowl = 0.25 cm Outer radius of hemispherical bowl = (5+0.25) cm = 5.25 cm Formula for outer CSA of hemispherical bowl = 2πr2, where r is radius of ... 22/7) (5.25)2 = 173.25 Therefore, the outer curved surface area of the bowl is 173.25 cm2.
Description : (i) The radius of a circle is increasing at the rate of 5 cm/sec. Find the rate of increasing of its perimeter. (ii) If the area of a circle increases
Last Answer : (i) The radius of a circle is increasing at the rate of 5 cm/sec. Find the rate ... to its circumference is iversely proportional to its radius.
Description : A balloon which always remains spherical, is being inflated by pumping in 900 cubic centimetres of gas per second. Find the rate at which the radius o
Last Answer : A balloon which always remains spherical, is being inflated by pumping in 900 cubic centimetres of gas ... is increasing when the radius is 15 cm.
Description : A balloon, which always remains spherical, has a variable diameter `3/2(2x+1)`.Find the rate of change of its volume with respect to x.
Last Answer : A balloon, which always remains spherical, has a variable diameter `3/2(2x+1)`.Find the rate of change of its volume ... (2)` D. `8/3 pi (2x+1)^(2)`
Description : The side of a square is increasing at a rate of 4cm/sec. Find the rate of increase of its area when the side of square is 10 cm.
Last Answer : The side of a square is increasing at a rate of 4cm/sec. Find the rate of increase of its area when the side of square is 10 cm.
Description : The radius of a spherical balloon increases -Maths 9th
Last Answer : Radius of the spherical balloon = r1 = 7 cm Surface area s1 of the balloon = 4 πr12 = 4 x 22/7 x 72 = 616 cm2 Radius of the spherical balloon when air is pumped into it = r2 = 14 cm Surface area S2 of the balloon = 4 πr22 = 4 x ... S 1/S 2 = 4 x 22/7 x 7 2/4 x 22/7 x14 2 = 1/4 ∴ S1 : S2 = 1 : 4
Description : What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water interface? The balloon is of radius 0.1 m and is filled with air. (A) 4πg/3 (B) 0.01 πgH/4 (C) 0.01 πgH/8 (D) 0.04 πgH/3
Last Answer : (A) 4πg/3
Description : Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find (i) radius of the base -Maths 9th
Last Answer : Slant height of cone, l = 14 cm Let the radius of the cone be r. (i) We know, CSA of cone = πrl Given: Curved surface area of a cone is 308 cm2 (308 ) = (22/7) r 14 308 = 44 r r = 308 ... Total surface area of cone = 308+(22/7) 72 = 308+154 Therefore, the total surface area of the cone is 462 cm2.
Description : The radius of a right circular cone is 3 cm and its height is 4 cm. The curved surface of the cone will be (1) 12 sq. cm (2) 15 sq. cm (3) 18 sq. cm (4) 21 sq. cm
Last Answer : (2) 15 sq. cm
Description : For minimum curved surface area and given volume, the ration of the height and radius of base of a cone is :
Last Answer : For minimum curved surface area and given volume, the ration of the height and radius of base of a cone is : A. ` ... : 1` C. `1 : 2` D. None of these
Description : A spherical metal of radius 10 cm is melted and made into 1000 smaller spheres of equal sizes. In this process the surface area of the -Maths 9th
Last Answer : Option (C) is correct. Solution: Let the radius of the small spheres be r' cm. Volume of metal remains the same in both cases. So, vol of the spherical metal of radius 10 cm = total ... Total Surface area of 1000 smaller spheres: 1000*4π12 = 4000π Hence, the surface area increased by 10 times.
Description : the curved surface area of a cylinder is 154 cm. the total surface area of the cylinder is three times its curved surface area. find the volume of the cylinder. -Maths 9th
Last Answer : T.S.A = 3*154 = 462 cm² C.S.A = 154 cm² C.S.A = 2πrh T.S.A = 2πr(r+h) Now, In T.S.A = 2πrr + 2πrh 462 = 2πrr + 2πrh 462 = 2*22/7*r*r + 154 462 - 154 = 2*22/7*r*r 308*7/2*22 = r*r 49 = r*r R = 7 cm ... 7*h 154/44 = h 7/2 =h H = 3.5 cm or 7/2 cm Now volume = πrrh = 22/7 * 7* 7 *7/2 = 11*49 = 539 cm³
Description : If the ratio of curved surface area and total surface area of a cylinder is 1 : 3, then find the volume of cylinder when the height is 2 cm. -Maths 9th
Last Answer : Let the radius and height of the cylinder be r and h, respectively . Given that, Curved surface area / Total surface area = 1/3 ⇒ 2πrh / 2πr(h + r) = 1/3 ⇒ 3h = h + r ⇒ r = 2h = 4cm ∴ volume of cylinder πr2h = π × (4)2 × 2 = 32π cm3
Description : The length of a rectangle is decreasing at a rate of 3 cm/sec and breadth is increasing at a rate of 4 cm/sec. Find the rate of change of its (a) peri
Last Answer : The length of a rectangle is decreasing at a rate of 3 cm/sec and breadth is increasing at a ... breadth of rectangle are 7 cm and 8 cm respectively.
Description : The side of a square is increasing at a rate of 3 cm/sec. Find the rate of increasing of its perimeter when the side of square is 5cm.
Last Answer : The side of a square is increasing at a rate of 3 cm/sec. Find the rate of increasing of its perimeter when the side of square is 5cm.
Description : The oil is leaking from a drum at a rate of `16 cm^(3)//sec`. If the radius and height of drum are 7 cm and 60 cm respectively, find the rate of chang
Last Answer : The oil is leaking from a drum at a rate of `16 cm^(3)//sec`. If the radius and height of drum ... height of oil when height of oil in drum is 18 cm.
Description : A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A ... (D) Effectiveness factor for a zero order reaction cannot be 7/8 as it must always be 1
Last Answer : (A) Inner catalyst core of radius R/8 does not participate in reaction (
Description : A cylindrical pillar is 50 cm in diameter and 3.5 m in height. Find the cost of painting the curved surface of the pillar at the rate of ₹12.50 per m2 . -Maths 9th
Last Answer : Diameter of the pillar = 50 cm ∴ Radius (r) = 502m = 25 m = 14m and height (h) = 3.5m Curved surface area of a pillar = 2πrh ∴ Curved surface area to be painted = 112m2 ∴ Cost of painting of 1 m2 pillar = Rs. 12.50 ∴ Cost of painting of 112 m2 pillar = Rs. ( 112 x 12.50 ) = Rs. 68.75.
Description : The radius of a hemispherical balloon increases from 6 cm to 12 cm as air is being pumped into it. -Maths 9th
Last Answer : NEED ANSWER
Last Answer : Find the ratios of the surface areas of the balloon in the two cases.
Description : 2. The radius of curvature of a spherical mirror is 20 cm. What is its focal length? -Physics-10
Last Answer : Radius of curvature (R) = 20 cm Radius of curvature of the spherical mirror = 2 × Focal length (f) R = 2f f= R/2 = 20 / 2 = 10 Therefore, the focal length of the spherical mirror is 10 cm.
Description : Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2 /sec.D1 = diffusion co-efficient; cm2 /sec L = length of the reactor, cm t = time, sec, v = volumetric ... (D/vL) (B) Reduced time (vt/V) (C) Thiele modulus L √(k/D1 ) (D) None of these
Last Answer : (D) None of these
Description : A shopkeeper has one spherical laddoo of radius 5 cm. With the same amount of material, how many laddoos of radius 2.5 cm can be made ? -Maths 9th
Last Answer : Radius of a big spherical laddoo = 5 cm ∴ Volume of the big spherical laddoo = 4 / 3 π 5 5 5 cm3 Radius of a small spherical laddoo = 2.5 = 5 / 2 cm ∴ Volume of the small spherical laddoo = 4 / ... = 2 2 2 = 8 Hence , with the same amount of big laddoo, 8 small laddoos can be made.
Description : A shopkeeper has one spherical laddoo of radius 5 cm. With the same amount of material, how many laddoos of radius 2.5 cm can be made? -Maths 9th
Last Answer : Solution of the question
Description : If in a cylinder, radius is doubled and height is halved, then find its curved surface area. -Maths 9th
Last Answer : Let r and h be radius and height of the cyclinder, then C.S.A. = 2πrh Now, radius is doubled and height is halved. ∴ New radius = 2r and new height = h / 2 New C.S.A. = 2π × 2r × h / 2 = 2πrh .
Description : Let angular value of one graduation of a tube of length be the radius of its internal curved surface, then (A) = x/206265 R (B) = R/206265 x (C) = 206265/x. R (D) = x. R/206265
Last Answer : (A) = x/206265 R
Description : A right circular cylinder just encloses a sphere of radius r (see fig. 13.22). Find (i) surface area of the sphere, (ii) curved surface area of the cylinder -Maths 9th
Last Answer : Surface area of sphere = 4πr2, where r is the radius of sphere (ii) Height of cylinder, h = r+r =2r Radius of cylinder = r CSA of cylinder formula = 2πrh = 2πr(2r) (using value of h) = 4πr2 (iii) Ratio ... sphere)/CSA of Cylinder) = 4r2/4r2 = 1/1 Ratio of the areas obtained in (i) and (ii) is 1:1.
Description : In a cylinder, radius is doubled and height is halved, then curved surface area will be -Maths 9th
Last Answer : The curved surface area will remain same. So, there is no change in the curved surface area of cylinder . Hence the curved surface area will remain same.
Description : If three cylinders of radius r and height h are placed vertically such that the curved surface of each cylinder touches the curved surfaces -Maths 9th
Last Answer : hr2 (3-√−π2)(3−π2) The bases of the three cylinders when placed as given are as shown in the figure : Let the radius of the base of each cylinder = r cm. We are required to find the volume of air. ... ∠C = 60º) = 3 x 60o360o πr2=πr2260o360o πr2=πr22 ∴ Required volume = (3-√r2−π2r2)h=(3-√−π2)r2h.
Description : if seve times the curved surface area (A) of a cylinder is equal to 44 times the proudct of base radius (r) and height (h) then what si the formula wi
Last Answer : if seve times the curved surface area (A) of a cylinder is equal to 44 times the proudct of base ... (h) then what si the formula with subject A?
Description : Which of the following statements about septic shock are true? A. A circulating myocardial depressant factor may account for the cardiac dysfunction sometimes seen with shock due to sepsis or ... animal studies that demonstrate a significant improvement in survival with the use of such agents.
Last Answer : Answer: AB DISCUSSION: Shock due to sepsis or SIRS frequently manifests as a hyperdynamic cardiovascular response, consisting of an elevated CI and a decreased SVR or SVRI. Occasionally, ... been encouraging thus far in human clinical trials, despite the promising results from many animal studies
Description : A flywheel weighs 400 kg and has a radius of gyration of 30 cm about its axis of rotation. It is mounted on a shaft subjected to a moment of 40 kgm. If the flywheel starts from restits speed after 3 seconds wil be a.10.9 rad/sec b.19.0 rad/sec c.51.2 rad/sec d.3.33 rad/sec e.16.35 rad/sec
Last Answer : d. 3.33 rad/sec
Description : The radius of a sphere decreases from 10 cm to `9.9` cm. Find (i) approximate decrease in its volume. (ii) approximate decrease in its surface.
Last Answer : The radius of a sphere decreases from 10 cm to `9.9` cm. Find (i) approximate decrease in its volume. (ii) approximate decrease in its surface.
Description : A balloon is inflated with helium gas at room temperature of 25 °C and at 1 bar pressure when its initial volume is 2.27L and allowed to rise in air.
Last Answer : A balloon is inflated with helium gas at room temperature of 25 °C and at 1 bar pressure when ... at which volume of the balloon can stay inflated ?
Description : A spherical convex surface separates object and image space of refractive index `1.0 and 4/3.` If radius of curvature of the surface is `10cm,` find i
Last Answer : A spherical convex surface separates object and image space of refractive index `1.0 and 4/3.` If ... of the surface is `10cm,` find its power.
Description : The centre of the reflecting surface of a spherical mirror is called the : (1) Radius (2) Centre of Curvature (3) Pole (4) Focus
Last Answer : (3) Pole Explanation: The center of the reflecting surface of a spherical mirron is called as the pole of the mirror which is mainly known as the center of curvature.
Description : The critical radius of insulation for a spherical shell is (where, K = thermal conductivity of insulating material h0 = heat transfer coefficient at the outer surface) (A) K/h0 (B) 2K/h0 (C) h0 /K (D) h0 /2K
Last Answer : (B) 2K/h0