-- From January 15 to February 6 is a period of 22 days.
-- The period of the full cycle of moon phases is 29.53 days.
-- So those dates represent (22/29.53) = 74.5% of a full cycle of phases.
-- That's almost exactly 3/4 of a full cycle, so on February 6, the moon would be almost exactly at <em>Third Quarter</em>. That's the <em>left half of a disk </em>(viewed from the northern hemisphere).
When a mirror is rotated . . .
-- The incident ray doesn't turn. It's just the line from the source to the mirror.
It would be there, in the same place, even if there was no mirror.
-- The normal turns. It's the line perpendicular to the mirror, so it must turn
with the mirror.
-- Since the normal tuns and the incident ray doesn't, the angle between them
must change. And since the angle of the reflected ray is equal to the angle of
the incident ray, the reflected ray must also turn.
D is the point where the planet moves the fastest. This is because it is in the perihelion, where the planet is moving at it’s fastest pace
-- The long line and short line close together at the left side
of the diagram represent a single-cell battery.
It's the only one in this diagram.
It's a device that stores chemical energy and delivers it on demand.
-- The zig-zag lines with circles around them represent light bulbs.
There are three of them in this diagram.
They are devices used to produce light by dissipating electrical energy.
-- The zig-zag lines without circles, at the top of the diagram,
represent resistors.
There are two of them in this diagram.
They are devices used to change or control electrical parameters
within a circuit by dissipating electrical energy.
-- The short straight line between two small circles at the bottom
of the diagram represents a switch.
There is only one switch in this circuit.
It's a device used to easily and quickly start or stop the flow of current
past a certain point in a circuit.
In this circuit ...
-- When the switch is closed (as drawn), the light bulb nearest the battery
glows brightest, the light bulb in the middle glows less bright, and the light
bulb on the right side glows dimmest of all.
-- When the switch is open, the light bulb nearest the battery glows, and
neither of the other two light bulbs glows at all.
