Consider the two-dimensional surface (“lamina”) bounded by y = e^x , y = 0, and x = 1 and whose density is given by ρ(x, y) = y. a) Find the mass of this lamina. b) Find the coordinates (x, y) of its center of mass.

Advanced Engineering Mathematics
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ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
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Consider the two-dimensional surface (“lamina”) bounded by y = e^x , y = 0, and x = 1 and whose density is given by ρ(x, y) = y.

a) Find the mass of this lamina.

b) Find the coordinates (x, y) of its center of mass.

### Problem Statement

---

**b) Find the coordinates \((\bar{x}, \bar{y})\) of its center of mass.**

---

This problem involves calculating the center of mass of an object or system. The center of mass is a critical concept in physics and engineering, representing the point where the mass of a system is considered to be concentrated. To find the center of mass coordinates, you will typically use the formulas:

\[ \bar{x} = \frac{\sum (x_i \cdot m_i)}{\sum m_i} \]
\[ \bar{y} = \frac{\sum (y_i \cdot m_i)}{\sum m_i} \]

where \(x_i\) and \(y_i\) are the coordinates of the individual masses \(m_i\) in the system. The total mass is denoted by \(\sum m_i\).

By solving these equations, you can determine the coordinates \((\bar{x}, \bar{y})\), which indicate the center of mass in the xy-plane.
Transcribed Image Text:### Problem Statement --- **b) Find the coordinates \((\bar{x}, \bar{y})\) of its center of mass.** --- This problem involves calculating the center of mass of an object or system. The center of mass is a critical concept in physics and engineering, representing the point where the mass of a system is considered to be concentrated. To find the center of mass coordinates, you will typically use the formulas: \[ \bar{x} = \frac{\sum (x_i \cdot m_i)}{\sum m_i} \] \[ \bar{y} = \frac{\sum (y_i \cdot m_i)}{\sum m_i} \] where \(x_i\) and \(y_i\) are the coordinates of the individual masses \(m_i\) in the system. The total mass is denoted by \(\sum m_i\). By solving these equations, you can determine the coordinates \((\bar{x}, \bar{y})\), which indicate the center of mass in the xy-plane.
### Problem Statement

**2)** Consider the two-dimensional surface ("lamina") bounded by \( y = e^x \), \( y = 0 \), and \( x = 1 \) and whose density is given by \( \rho(x,y) = y \).

**a)** Find the mass of this lamina.

### Explanation

We need to find the mass of the lamina with a density function \( \rho(x,y) = y \). The lamina is bounded by the curve \( y = e^x \), the line \( y = 0 \), and the line \( x = 1 \) in the \( xy \)-plane.

To calculate the mass, we use the double integral of the density function over the region \( R \) bounded by the given curves and lines:

\[ \text{Mass} = \iint_R \rho(x,y) \, dA = \iint_R y \, dA \]

First, we determine the limits of integration:
- The vertical slices (\( y \)-values) will range from \( y = 0 \) to \( y = e^x \).
- The horizontal slices (\( x \)-values) will range from \( x = 0 \) to \( x = 1 \).

Thus, the double integral becomes:

\[ \text{Mass} = \int_{0}^{1} \int_{0}^{e^x} y \, dy \, dx \]

### Solution Steps

1. **Integrate with respect to \( y \):**
   \[ \int_{0}^{e^x} y \, dy = \left[ \frac{y^2}{2} \right]_{0}^{e^x} = \frac{(e^x)^2}{2} - \frac{0^2}{2} = \frac{e^{2x}}{2} \]

2. **Integrate with respect to \( x \):**
   \[ \int_{0}^{1} \frac{e^{2x}}{2} \, dx = \frac{1}{2} \int_{0}^{1} e^{2x} \, dx \]

   To integrate \( e^{2x} \), use substitution:
   \[ u = 2x \implies du = 2 \, dx \implies dx = \frac
Transcribed Image Text:### Problem Statement **2)** Consider the two-dimensional surface ("lamina") bounded by \( y = e^x \), \( y = 0 \), and \( x = 1 \) and whose density is given by \( \rho(x,y) = y \). **a)** Find the mass of this lamina. ### Explanation We need to find the mass of the lamina with a density function \( \rho(x,y) = y \). The lamina is bounded by the curve \( y = e^x \), the line \( y = 0 \), and the line \( x = 1 \) in the \( xy \)-plane. To calculate the mass, we use the double integral of the density function over the region \( R \) bounded by the given curves and lines: \[ \text{Mass} = \iint_R \rho(x,y) \, dA = \iint_R y \, dA \] First, we determine the limits of integration: - The vertical slices (\( y \)-values) will range from \( y = 0 \) to \( y = e^x \). - The horizontal slices (\( x \)-values) will range from \( x = 0 \) to \( x = 1 \). Thus, the double integral becomes: \[ \text{Mass} = \int_{0}^{1} \int_{0}^{e^x} y \, dy \, dx \] ### Solution Steps 1. **Integrate with respect to \( y \):** \[ \int_{0}^{e^x} y \, dy = \left[ \frac{y^2}{2} \right]_{0}^{e^x} = \frac{(e^x)^2}{2} - \frac{0^2}{2} = \frac{e^{2x}}{2} \] 2. **Integrate with respect to \( x \):** \[ \int_{0}^{1} \frac{e^{2x}}{2} \, dx = \frac{1}{2} \int_{0}^{1} e^{2x} \, dx \] To integrate \( e^{2x} \), use substitution: \[ u = 2x \implies du = 2 \, dx \implies dx = \frac
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