Final answer:
To find the volume of the solid with a triangular base and equilateral triangular cross-sections, we integrate the area of the cross-sections along the y-axis from 0 to 5 based on the changing side length, which is a linear function of y.
Step-by-step explanation:
The problem requires finding the volume of a solid with a triangular base and equilateral triangular cross-sections perpendicular to the y-axis. The base of the solid, S, is a right triangle with vertices at (0, 0), (5, 0), and (0, 5). The height of each equilateral triangular cross-section at any point y is the distance from the point (y, 0) to the hypotenuse of the triangular base, which is linear and can be described by the equation x + y = 5. Because cross-sections are equilateral triangles, each side of a cross-section is twice the length of the height. Therefore, the area of a cross-section is ½∙height²∙√3.
As we move along the y-axis from 0 to 5, the length of a side of each cross-section decreases linearly from 5 to 0. We can integrate the area of these cross-sections from y = 0 to y = 5 to find the total volume of the solid. The integral for the calculation of volume is:
∫ (2∙(5-y))² × √3/4 dy from y=0 to y=5
Upon integrating, this gives us the volume of the solid S.