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analise essa imagem e responda as questões pedidas mostrando o passo a passo dos calcúlos.

Let's analyze the text from the image and address the mathematical questions presented.

### **Transcription of the Image:**

---

**Universidade Federal Rural da Amazônia**

**Instituto de Ciências Agrárias**

**Instituto Cheiroquímico**

**Faculdade: Engenharia Florestal**

**Disciplina: Física Aplicada**

**Professor: MSc. Darlan Holanda**

**Lista de Exercícios**

---

1. **(1ª)** A largura de uma rua reta, medida no tempo de atraso entre o instante que as sirenes posicionadas nas duas bordas da rua, foi medida como 3,5m. Em seguida, quando a sirene direita emitiu som, o tempo de atraso do som ouvido no lado esquerdo foi 0,01s. Assumindo que o som percorre 340 m/s, determine a largura da rua em metros. Os resultados devem ser dados com precisão de 0,01 m.

2. **(2ª)** Estime a área da seção transversal dessa rua.

3. **(3ª)** Considerando que a velocidade média de fluxo de ar, nessa seção transversal, é igual a 1,5 m/s, calcule a vazão em m³/s.

---

### **Solutions:**

#### **Question 1: Determining the Width of the Street**

The problem mentions that when a sound is emitted from one side of the street, it takes \( t = 0.01 \) seconds to be heard on the opposite side. Given that the speed of sound is \( v = 340 \, \text{m/s} \), we can calculate the width \( d \) of the street using the formula:

\[
d = v \times t
\]

Substituting the given values:

\[
d = 340 \, \text{m/s} \times 0.01 \, \text{s} = 3.40 \, \text{m}
\]

Thus, the width of the street is \( \mathbf{3.40 \, \text{m}} \).

#### **Question 2: Estimating the Cross-Sectional Area of the Street**

Assuming the street has a uniform width and is rectangular in shape, the cross-sectional area \( A \) can be estimated if we know the height. However, since the height is not given, we may assume it or consider the width as the primary dimension. If the height were provided or estimable, the area \( A \) would be calculated as:

\[
A = \text{width} \times \text{height}
\]

Since the height is not given, let's express the area in terms of width:

\[
A = d \times h
\]

Without height \( h \), this cannot be calculated explicitly.

#### **Question 3: Calculating the Airflow Rate (Vazão)**

The airflow rate \( Q \) can be calculated if the cross-sectional area and the average air velocity are known. The formula for flow rate is:

\[
Q = A \times v_{\text{air}}
\]

Where \( A \) is the cross-sectional area, and \( v_{\text{air}} \) is the average air velocity.

Given:
- \( v_{\text{air}} = 1.5 \, \text{m/s} \)
- The area \( A \) must be calculated or estimated based on the cross-section.

Substituting the cross-sectional area (if we assume a hypothetical height \( h \) or if known):

\[
Q = A \times 1.5 \, \text{m/s}
\]

### **Clarifications:**
- For the second question, if you can provide or estimate the height, I can calculate the exact area.
- Similarly, the flow rate depends on the area obtained.

Would you like to estimate a height, or do you need further assistance on how to proceed?

### **Related Questions:**

1. What would be the effect on the width calculation if the speed of sound changed?
2. How would the flow rate change if the air velocity doubled?
3. What assumptions are inherent in calculating the width using sound?
4. How does the cross-sectional area affect the airflow rate in real-world scenarios?
5. How can we determine the height of the street if it’s not provided?

**Tip:** When dealing with sound propagation for measurements, always ensure to consider factors like air temperature, which can affect the speed of sound.

Explore the physics of sound propagation applied to calculate street width, cross-sectional area, and airflow rate. Detailed step-by-step solutions and formulas included. Suitable for university-level students and physics enthusiasts.

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