Answered

Compute the amplitude of the particular solution for the undamped system acted on by an external force \( F(t) = Fe^{j 2 \pi f t} \).

[tex]\[
X = \frac{\frac{F}{k}}{1 - \frac{(2 \pi f)^2 m}{k}}
\][/tex]



Answer :

To find the amplitude of the particular solution for the undamped system acted on by an external force, we use the provided formula:

[tex]\[ X = \frac{\frac{F}{k}}{1 - \frac{(2 \pi f)^2 m}{k}} \][/tex]

We are given:
- \( F \) (external force)
- \( k \) (spring constant)
- \( f \) (frequency)
- \( m \) (mass)

For simplicity, let's use the following example values (note that these values are for the sake of explaining the solution):
- \( F = 1 \) (in appropriate units)
- \( k = 1 \) (in appropriate units)
- \( f = 1 \) (in Hz)
- \( m = 1 \) (in kg)

Now, let's substitute these values into the formula and compute step-by-step.

1. Compute \(\frac{F}{k}\):

[tex]\[ \frac{F}{k} = \frac{1}{1} = 1 \][/tex]

2. Compute \((2 \pi f)^2 m\):
- First, compute \(2 \pi f\):

[tex]\[ 2 \pi f = 2 \pi \times 1 = 2 \pi \][/tex]

- Now square it:

[tex]\[ (2 \pi)^2 = (2 \pi)^2 = 4 \pi^2 \][/tex]

- Finally, multiply by \(m\):

[tex]\[ (4 \pi^2) \times 1 = 4 \pi^2 \][/tex]

3. Compute \(\frac{(2 \pi f)^2 m}{k}\):

[tex]\[ \frac{(2 \pi f)^2 m}{k} = \frac{(4 \pi^2) \times 1}{1} = 4 \pi^2 \][/tex]

4. Substitute these results into the denominator:

[tex]\[ 1 - \frac{(2 \pi f)^2 m}{k} = 1 - 4 \pi^2 \][/tex]

5. Combine the numerator and the denominator:

[tex]\[ X = \frac{1}{1 - 4 \pi^2} \][/tex]

Using the values we computed:

[tex]\[ 1 - 4 \pi^2 \approx 1 - 39.4784 \approx -38.4784 \][/tex]

So,

[tex]\[ X \approx \frac{1}{-38.4784} \approx -0.025988594704756167 \][/tex]

Therefore, the amplitude of the particular solution \( X \) is approximately:

[tex]\[ X \approx -0.025988594704756167 \][/tex]