Why Does the Phase Shift in the Sunrise Equation Equal 10 Days?

In summary, the sunrise times in Estevan, Saskatchewan can be predicted using a sinusoidal equation with a period of 365 days. The latest sunrise occurs at 9:12am on Dec 21 and the earliest sunrise occurs at 3:12am on June 21. The equation is given by D=180cos(2*pi*(t-10)/365)+372, where D represents the number of days and t represents the time of year. The phase shift of the equation is equal to 10 because the base information for the latest and earliest sunrises occurs 10 days before the start of the calendar year.
  • #1
At Estevan, Saskatchewan, the latest sunrise time is at 9:12am on Dec 21. The earliest sunrise time is 3:12pm on June 21. Sunrise times on other dates can be predicted from a sinusoidal equation. There is no daylight saving time in Saskatchewan and the period is 365 days. Convert the time into minutes and the date into days. That is, June 21 is 172 days and Dec 21 is 355.

The equation is given by


where D=days and t=time

Does anyone know why the phase shift is equal to 10?
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  • #2
Strictly speaking, the phase shift is 20pi/365. But the "10" is there because t represents the day of the year starting at Jan.1 and the base information, latest and earliest sunrises, is at Dec. 21 and June 21, 10 days earlier than the beginning and middle of the calendar year.

Related to Why Does the Phase Shift in the Sunrise Equation Equal 10 Days?

1. Why is the phase shift equal in sinusoidal signals?

The phase shift in sinusoidal signals refers to the difference in the starting point or phase angle of two different signals with the same frequency. This shift occurs due to a delay in the signal, which can be caused by various factors such as the medium through which the signal is traveling or the components in the circuit. When the phase shift is equal, it means that the two signals have the same starting point and are in phase with each other.

2. How does the phase shift affect the behavior of sinusoidal signals?

The phase shift can significantly impact the behavior of sinusoidal signals. When two signals are in phase (equal phase shift), they will add constructively, resulting in a higher amplitude signal. On the other hand, if two signals are out of phase, they will add destructively, resulting in a lower amplitude signal. This behavior is essential in applications such as signal processing and audio engineering.

3. What is the relationship between frequency and phase shift?

Frequency and phase shift have an inverse relationship. This means that as the frequency of a sinusoidal signal increases, the phase shift decreases. For example, if we have two signals with the same amplitude and phase but different frequencies, the higher frequency signal will have a lower phase shift compared to the lower frequency signal. This relationship is crucial in understanding the behavior of signals in various applications.

4. Can the phase shift be measured and controlled?

Yes, the phase shift can be measured and controlled in various ways. In electronic circuits, phase shift can be controlled using devices such as capacitors and inductors. In signal processing applications, the phase shift can be measured using tools such as oscilloscopes or spectral analyzers. Additionally, techniques such as phase modulation and phase shifting can also be used to control the phase shift in signals.

5. How is the phase shift represented mathematically?

The phase shift is represented mathematically using the phase angle (ϕ), which is measured in degrees or radians. It is also common to represent the phase shift as a fraction of the signal's period, known as the phase shift coefficient (α). The phase shift coefficient is expressed as a decimal or a percentage. It is essential to understand these mathematical representations to analyze and manipulate signals with different phase shifts.

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