Question 149 of 949
A travelling wave moving from left to right has an amplitude of 0.15m, a frequency of 550Hz and a wavelength of 0.01m. The equation describing the wave is
- A. y = 0.15 sin 200π(x - 5.5t)
- B. y = 0.15 sin π(0.01x - 5.5t)
- C. y = 0.15 sin 5.5π(x - 200t)
- D. y = 0.15 sin π(550x - 0.01t)
Correct Answer:
A
Explanation
To determine the correct equation for the traveling wave described in the question, we need to analyze the parameters given: amplitude, frequency, and wavelength.
### Given Parameters:
- **Amplitude (A)**: 0.15 m
- **Frequency (f)**: 550 Hz
- **Wavelength (λ)**: 0.01 m
### Step 1: Understanding Wave Equation
The general form of a traveling wave can be expressed as:
\[ y(x, t) = A \sin(kx - \omega t) \]
where:
- \( A \) is the amplitude,
- \( k \) is the wave number,
- \( \omega \) is the angular frequency,
- \( x \) is the position,
- \( t \) is the time.
### Step 2: Calculate Wave Number (k) and Angular Frequency (ω)
1. **Wave Number (k)**:
The wave number \( k \) is given by the formula:
\[ k = \frac{2\pi}{\lambda} \]
Substituting the wavelength:
\[ k = \frac{2\pi}{0.01} = 200\pi \, \text{m}^{-1} \]
2. **Angular Frequency (ω)**:
The angular frequency \( \omega \) is given by:
\[ \omega = 2\pi f \]
Substituting the frequency:
\[ \omega = 2\pi \times 550 = 1100\pi \, \text{rad/s} \]
### Step 3: Formulate the Wave Equation
Now we can substitute the values of \( A \), \( k \), and \( \omega \) into the wave equation:
\[ y(x, t) = 0.15 \sin(200\pi x - 1100\pi t) \]
### Step 4: Rearranging the Equation
The equation can be rearranged to match the form in the options:
\[ y = 0.15 \sin(200\pi (x - 5.5t)) \]
This is because \( 1100\pi = 200\pi \times 5.5 \).
### Step 5: Identify the Correct Option
Now, let's compare this derived equation with the options provided:
- **Option A**: \( y = 0.15 \sin(200\pi(x - 5.5t)) \) - **This matches our derived equation.**
- **Option B**: \( y = 0.15 \sin(\pi(0.01x - 5.5t)) \) - This does not match because the wave number and angular frequency are incorrect.
- **Option C**: \( y = 0.15 \sin(5.5\pi(x - 200t)) \) - This is incorrect as the coefficients do not match the calculated values.
- **Option D**: \( y = 0.15 \sin(\pi(550x - 0.01t)) \) - This is incorrect because the terms inside the sine function do not correspond to the correct wave number and angular frequency.
### Conclusion
The correct option is **A**: \( y = 0.15 \sin(200\pi(x - 5.5t)) \).
### Revision Summary:
- The wave equation is derived from amplitude, frequency, and wavelength.
- Wave number \( k \) is calculated as \( k = \frac{2\pi}{\lambda} \).
- Angular frequency \( \omega \) is calculated as \( \omega = 2\pi f \).
- The correct wave equation matches the derived form, confirming option A as correct.