Teaching Notes

[admin]

The cork accelerometer will indicate an acceleration
toward the center of the circular path in which the
accelerometer moves.
SAFETY PRECAUTION: If a rotating stool or chair
is used to place a student holding an accelerometer
in a state of circular motion, provide close
supervision and maintain safe conditions; the effect
can be observed without a rotating stool or chair if
students simply twirl around while holding an
accelerometer in the hands.
If students have not already done so, some time
may be required to familiarize them with the use of
the accelerometer.
Students can be expected to need practice at keeping alongside the ball while applying a constant force always sideways (at a right angle to) the ball’s
motion; in fact, to do so extremely well perhaps is nearly impossible, but “close” will do well enough for students to observe the tendency for the ball to
move in a circular path.
Some students may raise the question, “How can there be an acceleration when the object moves at constant speed?” You may wish to see the
explanation in the Background Information for the
Teacher for this activity to decide how you will deal with that question.
Students also may ask about, or bring up,
“centrifugal force.” This is addressed in the
Background Information for the Teacher. A first
response to a question about centrifugal force would
be to refer students to Physics To Go, Question 2.
Students may have an inclination to “run together,”
or treat as the same phenomenon, circular motion
with spinning motion. They are separate, but
related, phenomena. This activity applies to the
former, an object whose center of mass is movingalong a circular path. When a figure skater does anin-place spin, the skater’s center of mass does not
move; it is a different phenomenon. It is possible, however, to treat part of the skater, such as anextended foot at the end of the spin, as an object incircular motion to which the ideas in this activity could be applied.

[Tracy Greeley-Adams]

I have no idea why this is here.  In this activity the students jump in the air and i do not see anything regarding an accelerameter.  am I wrong??  I actually wanted to post because the FYTD states we are to watch a video but I did not receive the video.  Did anyone else??  was there another place some one knows were to look for this??

Just trying to prepare for my next activity before the chapter challenge!!

[Matt Anthes-Washburn]

Looks like it's from the old activity 9, Circular Motion. That explains the confusion!