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Coal is pouring from a high conveyor belt onto a conical pile. The conical pile has a semi-vertical angle of 30°, and at time t the radius of the base is r.

a) Find the height of the cone in terms of r.
b) Show that the volume V of the cone is ( π r³/ √33 ).

1 Answer

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Final answer:

The height of a conical pile with a semi-vertical angle of 30° and base radius r is h = r. The volume of the cone is V = \(\frac{1}{3}\)\pi r^3, not V = \(\frac{\pi r^3}{\sqrt{33}}\) as mentioned in the question, which is a mistake.

Step-by-step explanation:

The question involves finding the height of a conical pile (part a) and the volume of the cone (part b) given the semi-vertical angle of 30°. For part a, since the semi-vertical angle is 30°, the height can be found by the relation in a 30-60-90 right triangle where the height (h) is the same as the radius (r), so h = r. For part b, the volume of a cone is V = \(\frac{1}{3}\)\pi r^2h. Since we know from part a that h = r, we can substitute h with r to get V = \(\frac{1}{3}\)\pi r^3. However, there is a typographical error in the question outlining the volume formula to be V = \(\frac{\pi r^3}{\sqrt{33}}\), which is incorrect and should be corrected as the former.

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