Moderate 867 likes

Question

The curved surface area of ​​a right circular cylindrical wooden log of uniform density is 440 sq. decimeters. The weight of 1 cubic decimeter of wood is 3 kg and the weight of a log is 18.48 quintals. Find the diameter of the log.

WBBSE Class X Mathematics Right Circular Cylinder 04 Mark 2023

Answer

Given:

  • Curved surface area = 440 sq. decimeters
  • Density of the wood = 3 kg per cubic decimeter
  • Weight of the log = 18.48 quintals (1 quintal = 100 kg)

Convert the weight of the log to kilograms:

Weight of the log = 18.48 × 100 = 1848 kg

Formula for the curved surface area (CSA) of a cylinder:

CSA = 2πrh

Given that CSA = 440:

2πrh = 440 — (1)

Volume of the cylinder:

Volume = πr²h

Weight of the log = Volume × Density

1848 = πr²h × 3

πr²h = 616 — (2)

Divide the second equation by the first:

πr²h \over 2πrh = 616 \over 440

r \over 2 = 14 \over 10

r = 2.8 decimeters

Diameter = 2r = 2 × 2.8 = 5.6 decimeters

Therefore, the diameter of the log is 5.6 decimeters.

Related Questions

More WBBSE Moderate level questions

1/12
Moderate
Q. How can the given conversion be carried out?
A. The given conversion of ethene (H₂C = CH₂) to ethane (H₃C –...
Moderate
Q. State the resistance of 220 V – 100 W bulb
A. Power (P) = Resistance (R) = = = = 484 Ω
Moderate
Q. For which value of the angle of incidence in refraction of light is Snell’s law...
A. Snell’s law is not applicable when the angle of incidence is 0°.
Moderate
Q. Write whether the following statement is true or false: If coefficient of linear expansion of...
A. True Explanation: Coefficient of cubical expansion γ = 3 × coefficient of...
Moderate
Q. What is the number of molecules present in 16 g of O₂ at S.T.P.?
A. 3.011 × 10²³ Explanation: Given mass = 16 g Molecular mass =...
Moderate
Q. Write whether the following statement is true or false: According to Charles’ law, at (–)...
A. False Explanation: Charles' law states volume becomes zero at absolute zero (-273°C),...
Moderate
Q. Write the name of monomer of a polymer which is used to prepare non-stick utensils.
A. Tetra fluoro ethylene Explanation: Polytetrafluoroethylene (PTFE or Teflon) is used for non-stick...
Moderate
Q. Write down the IUPAC name of the following organic compound
A. 2-Bromopropane or (1) CH₃–CH₂–CH₂–OH → Propane-1-ol(2) CH₃–CH(OH)–CH₃ → Propane-2-ol
Moderate
Q. Name the metal which is extracted in thermite process.
A. Fe Explanation: Thermite process reduces metal oxides using Al at high temperature...
Moderate
Q. Fill up the blank: CaC₂ + N₂ → ____ + C
A. CaNCN / CaCN₂ (Calcium cyanamide) Explanation: Haber's process uses Fe as catalyst...
Moderate
Q. What happens when an iron spoon is dipped into acidified copper sulphate solution?
A. When an iron spoon is dipped into acidified copper sulphate solution, a...
Moderate
Q. Left Column 2.2.1 Metal present in German silver 2.2.2 A transuranium element 2.2.3 The metal...
A. 2.2.1 – (d), 2.2.2 – (c), 2.2.3 – (b), 2.2.4 – (a).​...