Under the Indian Posts and Telegraph Act 1885, any package in the form...
Volume is maximum when radius is equal to height.
View all questions of this test
Under the Indian Posts and Telegraph Act 1885, any package in the form...
Explanation:
Given:
- According to the Indian Posts and Telegraph Act 1885, the sum of the height and the diameter of a right circular cylinder should not exceed 10 inches.
- We need to find the height of the cylinder with the maximum volume that would be accepted under this rule.
Formula for volume of a cylinder:
- The volume of a cylinder is given by the formula V = πr^2h, where r is the radius and h is the height of the cylinder.
Expressing diameter in terms of radius:
- Since the sum of the height and the diameter should not exceed 10 inches, we can express the diameter in terms of radius as d = 2r.
- Therefore, the sum of the height and the diameter can be written as h + 2r ≤ 10.
Expressing height in terms of radius:
- We need to express the height in terms of the radius to determine the maximum volume of the cylinder.
- From the given condition, h + 2r ≤ 10, we can express the height as h = 10 - 2r.
Substitute height in volume formula:
- Substituting the expression for height in terms of radius into the formula for the volume of a cylinder, we get V = πr^2(10 - 2r).
Finding maximum volume:
- To find the maximum volume, we need to differentiate the volume formula with respect to r, set it equal to zero, and solve for r.
- Differentiating the volume formula and setting it to zero, we get dV/dr = 0 ⇒ 20πr - 6πr^2 = 0 ⇒ r(20 - 6r) = 0.
- Solving for r, we get r = 0 or r = 20/6 = 10/3.
Calculating maximum height:
- Since the height is h = 10 - 2r, we can substitute r = 10/3 to find the maximum height.
- Therefore, h = 10 - 2(10/3) = 10/3 inches.
Conclusion:
- The height of a package of maximum volume that would be accepted under the given condition is 10/3 inches. Hence, the correct answer is option 'A'.