Question

The theorem of Pappus and Guldinus states that the area of the revolving curve is ______________

(a) Product of the area, length of the generated curve and the radius vector

(b) Product of the area, length of the generated curve and the perpendicular distance from axis

(c) Product of the volume, length of the generated curve and the radius vector

(d) Product of the volume, length of the generated curve and the perpendicular distance from axis

The question was posed to me in class test.

Query is from Theorem of Pappus and Guldinus topic in chapter Centre of Gravity and Centroid of Engineering Mechanics

Answer 1

Right answer is (b) Product of the area, length of the generated curve and the perpendicular distance from axis

To explain I would say: The theorem is used to find the surface area and the volume of the revolving body. This is done by using simple integration. Thus the surface area and the volume of any 2D curve. It is just the product of the area, length of generated curve and the perpendicular distance from axis.