To find the ratio of the amplitudes of the two equations representing simple harmonic motion (SHM), we first need to identify the amplitudes from each equation. The equations given are:
Understanding the Equations
The first equation is:
y1 = a sin(wt)
In this equation, the amplitude is simply the coefficient of the sine function, which is a.
The second equation is:
y2 = (a/2)(sin(wt) + cos(wt))
To find the amplitude of this equation, we need to analyze the expression inside the parentheses. The terms sin(wt) and cos(wt) can be combined into a single sinusoidal function using the formula for the amplitude of a sum of sine and cosine functions.
Combining Sine and Cosine
When you have a combination of sine and cosine, you can express it as:
A sin(wt + φ)
where A is the resultant amplitude and φ is the phase shift. The amplitude can be calculated using the formula:
A = √(A1² + A2²)
Here, A1 is the coefficient of sin(wt) (which is 1) and A2 is the coefficient of cos(wt) (which is also 1).
Calculating the Amplitude
Substituting the values:
A = √(1² + 1²) = √(1 + 1) = √2
Now, since the entire expression for y2 is multiplied by a/2, the amplitude of y2 becomes:
Amplitude of y2 = (a/2) * √2
Finding the Ratio of Amplitudes
Now that we have the amplitudes of both equations, we can find the ratio:
Amplitude of y1 = a
Amplitude of y2 = (a/2) * √2
The ratio of the amplitudes is:
Ratio = Amplitude of y1 / Amplitude of y2
Ratio = a / ((a/2) * √2)
Simplifying the Ratio
To simplify this expression:
Ratio = a / (a/2) * (1/√2) = (a * 2) / (a * √2) = 2 / √2
Now, simplifying further:
2 / √2 = √2
Final Result
Thus, the ratio of the amplitudes of the two equations is:
√2
This means that the amplitude of the first equation is √2 times greater than that of the second equation. This relationship highlights how different forms of SHM can have varying amplitudes even when they are derived from similar trigonometric functions.