Why are tide graphs sinusoidal? (sin graphs)?

Answer 1

Well, I don't think they're exactly sinusoidal, but yes, they do go up and down with a constant period.

The reason they do that is that the force of the moon's gravity on any particular location on earth follows a regular pattern of increasing and decreasing as the earth rotates beneath the moon. The period of a complete cycle is the time from when the moon passes over a particular meridian one day, until it passes the same meridian the next day. This is slightly longer than 24 hours, since the moon is orbiting the earth in the same direction that the earth is turning, so the earth has to turn a bit more than one complete rotation to catch up to where the moon has moved in one day.

If you work out the physics of it, it turns out that the tides rise and fall (one complete sin wave cycle) twice each day (or twice in a bit more than a day, as just explained). You can do a web search to learn why it happens twice a day.

But it's not exactly a sin wave, because the sun also has an effect on tides, and this effect increases and decreases as the phase of the moon changes (greatest during a new moon when the sun and moon are on the same side of the earth). and the moon's orbit is not directly above the equator, so its effect on the tides changes periodically due to the earth's tilts, just as the earth's tilt causes seasons.

Answer 2

C is the appropriate answer. start up on the x axis at 0 and pass up 4 on the y axis. -2/3 is the slope intercept so as which you will pass down 2 and to the main remarkable 3 because of the fact the three is useful.