Math Problem Statement

A volume is described as follows: The base is the region bounded by y=6−38x2y=6-38x2 and y=0,y=0, and every cross section parallel to the xx-axis is a right triangle whose height and base are equal, and the base of the right triangle lies along the base of the region.

Find the volume of this object.

Volume =

Solution

To find the volume of the given solid, we need to break it down step by step.

1. Base of the Region:

The base of the solid is the region bounded by the curves:

  • y=638x2y = 6 - 38x^2
  • y=0y = 0

This represents a parabola opening downward, and the base region extends from y=0y = 0 to the curve.

2. Shape of the Cross Sections:

Each cross section of the solid parallel to the xx-axis is a right triangle. The important points here are:

  • The base of the triangle lies along the base of the region.
  • The height of each triangle is equal to its base.

So, if the base of a triangle is b(x)b(x), then the height is also b(x)b(x).

3. Base of the Triangle:

The base of each triangle at a given value of xx is the vertical distance from the xx-axis (where y=0y = 0) to the curve y=638x2y = 6 - 38x^2. This is simply 638x26 - 38x^2.

So, the base and height of each triangle are both 638x26 - 38x^2.

4. Area of the Cross Section:

For a right triangle, the area A(x)A(x) is given by:

A(x)=12(base)×(height)A(x) = \frac{1}{2} \text{(base)} \times \text{(height)}

Since the base and height are both 638x26 - 38x^2, we have:

A(x)=12(638x2)2A(x) = \frac{1}{2} (6 - 38x^2)^2

5. Volume of the Solid:

To find the total volume, we integrate the area of the cross sections over the interval where the region exists. First, let's find the limits of integration.

Since y=638x2y = 6 - 38x^2 is bounded by y=0y = 0, we need to solve for the xx-values where y=0y = 0:

638x2=06 - 38x^2 = 0

38x2=638x^2 = 6

x2=638=319x^2 = \frac{6}{38} = \frac{3}{19}

x=±319x = \pm \sqrt{\frac{3}{19}}

Thus, the region extends from x=319x = -\sqrt{\frac{3}{19}} to x=319x = \sqrt{\frac{3}{19}}.

Now, we compute the volume by integrating the area function:

V=31931912(638x2)2dxV = \int_{-\sqrt{\frac{3}{19}}}^{\sqrt{\frac{3}{19}}} \frac{1}{2} (6 - 38x^2)^2 \, dx

Let me calculate this for you.The volume of the solid is approximately 7.637.63 cubic units.

Would you like further clarification on the steps, or any more details?

Here are some related questions to deepen understanding:

  1. How would the volume change if the height of each cross-section was double the base?
  2. What would the integral look like if the cross-sections were equilateral triangles instead of right triangles?
  3. Can you find the centroid of the base region described by y=638x2y = 6 - 38x^2?
  4. How does the shape of the parabola affect the overall volume?
  5. How would the volume change if the bounds for xx were extended or narrowed?

Tip: Understanding how the cross-sectional shape impacts the volume is crucial for visualizing and solving more complex solids.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Integration
Geometric Solids
Cross-sectional Area
Parabolas

Formulas

Area of a right triangle: A = 1/2 * base * height
Volume of a solid with cross-sectional area: V = ∫ A(x) dx

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12, College Calculus