/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 37 Compute work as described in Sec... [FREE SOLUTION] | 91Ó°ÊÓ

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Compute work as described in Sec. \(24.4,\) but use the following equations for \(F(x)\) and \(\theta(x)\) $$\begin{array}{l} F(x)=1.6 x-0.045 x^{2} \\ \theta(x)=-0.00055 x^{3}+0.0123 x^{2}+0.13 x \end{array}$$ The force is in newtons and the angle is in radians. Perform the integration from \(x=0\) to \(30 \mathrm{m}\)

Short Answer

Expert verified
The total work done can be found by calculating the horizontal component of force, \(F_x(x)\), by using the given equations for \(F(x)\) and \(\theta(x)\), and then integrating \(F_x(x)\) from x = 0 to x = 30 meters: \[W = \int_{0}^{30} (1.6x - 0.045x^2) \cdot \cos(-0.00055x^3 + 0.0123x^2 + 0.13x) dx\] As the integral cannot be solved analytically, we must use numerical integration techniques or computational tools to obtain a definite value for the work done.

Step by step solution

01

Find the horizontal component of force

As we know from the given text, the force, \(F(x)\), varies with position, x, and the angle, theta, is given as a function of position. To find the horizontal component of force, \(F_x\), we will use the following relation: \[F_x(x) = F(x) \cdot \cos(\theta(x))\] Substitute the given functions for \(F(x)\) and \(\theta(x)\): \[F_x(x) = (1.6x - 0.045x^2) \cdot \cos(-0.00055x^3 + 0.0123x^2 + 0.13x)\]
02

Integrate the horizontal component of force to find work

Now, to find the total work done, we need to integrate \(F_x(x)\) from x = 0 to x = 30 meters: \[W = \int_{0}^{30} F_x(x) dx = \int_{0}^{30} (1.6x - 0.045x^2) \cdot \cos(-0.00055x^3 + 0.0123x^2 + 0.13x) dx\] Unfortunately, this integral cannot be solved analytically, so we need to resort to numerical integration techniques such as the Simpson's method or the trapezoidal rule. A definite numerical value for the work done can be obtained using computational tools such as Wolfram Alpha or Matlab.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Numerical Integration
Numerical Integration is a powerful tool we use in mathematics and physics to find the area under a curve when an analytical solution is tricky or impossible. In our exercise, we needed to find the work done by a force, which involves integrating the horizontal force, \(F_x(x)\), over a path from \(x=0\) to \(x=30\) meters.
Analytical solutions may not be straightforward, particularly when dealing with complicated functions like our problem's combination of quadratic and trigonometric functions.
Therefore, numerical methods step in to approximate this integral. To perform numerical integration, popular techniques include:
  • Trapezoidal Rule: It approximates the curve as a series of trapezoids and calculates the total area. It's simple but might not be as accurate for functions with high curvature.
  • Simpson's Rule: This is more accurate, especially for polynomial functions, because it uses parabolas to approximate sections of the curve.
These methods allow us to compute otherwise complex integrals by converting them into simple arithmetic tasks handled by a computer or calculator.
Forces and Motion
In physics, understanding forces and motion is crucial to computing the work done by a force. The concept of work relates directly to how a force moves an object over some distance. Work is defined as the force applied in the direction of motion multiplied by the displacement.In our exercise, we broke forces into components:
  • Force: In this context, the force \(F(x)\) is a function of position \(x\). It is not constant but changes with position.
  • Angle: The angle \(\theta(x)\) determines how much of this force contributes to the displacement in the desired direction, adjusting the effective component of force that does work.
We determine the horizontal component of force, \(F_x\), using \(\cos(\theta(x))\), since cosine computes how much of the force vector lies in its direction of motion. The integration of \(F_x(x)\) across a specific distance gives the total work done, encapsulating the idea that work depends on both force applied and the motion it causes.
Trigonometric Functions in Physics
Trigonometric functions, like sine and cosine, are waveforms that help describe how angles and relationships in physics evolve, particularly in evaluating components of vectors.In our problem, we use the cosine function because it relates directly to the directional aspect of a force. When we have forces acting at angles, it's crucial to break them into components using trigonometric identities.Here's why cosine is relevant:- **Angle of force**: The angle \(\theta(x)\) modifies how much of our force \(F(x)\) contributes to motion.- **Component calculation**: By computing \(\cos(\theta(x))\), we convert the entire force vector into its usable horizontal component.In many mechanics problems, breaking vectors into components using trigonometric functions like cosine allows us to simplify complex 2D or 3D force interactions into manageable calculations. This makes tasks such as calculating work more straightforward and mathematically feasible.

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Most popular questions from this chapter

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