5.7
Problem Solving: Volume
The volume of a fuel tank mounted on the wing of a jet aircraft can be modeled using the concept of solids of revolution. In this case, the tank is fo…
A fuel tank mounted on the wing of a jet aircraft is formed by rotating a region about the central axis. This region is formed by rotating a mathematical function about the x-axis and extends from zero to two meters.
To find the volume of the tank, the disk method is used, which involves slicing the solid into infinitesimally thin circular disks perpendicular to the x-axis.
Each disk has an area equal to 𝜋 times the square of the function's value. The total volume is found by integrating these areas over the interval.
After squaring the function, the integrand simplifies to a constant multiplied by the second power of x and the difference between two and x.
Expanding and integrating this expression produces an antiderivative involving the third and fourth powers of x.
Evaluating the definite integral from zero to two and substituting the limits gives an expression. Further simplifying yields a volume of approximately 1 cubic meter, which is the total volume of the fuel tank.
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Q1: What is the disk method and how does it apply to finding volume?
The disk method divides a solid of revolution into infinitesimally thin circular disks perpendicular to the axis of rotation. Each disk's area equals π times the square of the function's radius value. By integrating these disk areas over the specified interval, you accumulate the total volume of the solid using calculation of volume of solids by integration.
Q2: How is a fuel tank modeled as a solid of revolution?
A fuel tank is modeled by rotating a two-dimensional region defined by a mathematical function about the x-axis. The region extends from zero to two meters along the axis, creating a three-dimensional symmetric shape. This approach allows engineers to calculate precise fuel capacity and weight distribution for aircraft performance.
Q3: What steps are involved in calculating the volume using integration?
First, square the function defining the tank's boundary to get the disk area formula. Then expand the resulting expression to identify terms with third and fourth powers of the variable. Finally, integrate these terms over the interval from zero to two meters and evaluate the definite integral by substituting the limits.
Q4: Why is the disk method appropriate for this fuel tank problem?
The disk method is appropriate because the boundary curve lies directly against the axis of rotation, creating circular cross-sections perpendicular to the x-axis. This geometry allows each disk's radius to equal the function value at that position, making the method straightforward and accurate for calculating the tank's volume.
Q5: What does the antiderivative represent in this volume calculation?
The antiderivative describes how volume accumulates along the axis of integration as you move from zero to two meters. It captures the cumulative effect of all infinitesimal disk areas stacked along the tank's length. Evaluating this antiderivative at the limits yields the total internal capacity of approximately one cubic meter.
Q6: How does the definite integral produce the final volume result?
The definite integral evaluates the antiderivative at the upper limit of two meters and subtracts its value at the lower limit of zero. This calculation yields a numerical result that simplifies to approximately one cubic meter, representing the total fuel tank capacity needed for aerospace engineering applications.
Q7: Why is precise volume calculation critical in aerospace engineering?
Accurate volume estimates determine fuel capacity, weight distribution, and overall aircraft performance. Engineers must know exact tank dimensions to optimize fuel storage, balance aircraft weight, and ensure safe flight operations. Mathematical modeling through integration provides the precision necessary for reliable aerospace design and safety.