Wednesday, April 9, 2008

This class we got a lot of work done. We first started by going over the Centripetal Acceleration and Centripetal Force worksheet. It was pretty simple, basically plugging in numbers into the formulas. Next, we went over the Acceleration and Circular Motion worksheet. It involved the car and directions of the force. It was pretty straight forward and was almost all common sense. Then Ms. K handed out a worksheet titled Centripetal and Centrifugal Forces. Please make sure to read over this as it is very necessary. We also picked up another Study Guide based on Work and Energy, as our next topic. Fun, quick, easy class!

Next scribe will be Robert.

Today's lesson

Today Ms.K showed us how to derive the equation for centripetal acceleration. After that we worked on the worksheet called centripetal acceleration that was given before the break. Those people that had missed the lab from yesterday did that today as well.
Tomorrow's scribe will be........Bertman

Derivation of Centripetal Acceleration

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Welcome back!

Hello everyone, it's Allyson.

I hope everyone had a well rested and fun spring break. I sure did. But now it's back to school and it's time to pull up our socks because grad is just around the corner. =(

Anyways in class today we did a lab on Centripetal Force. We timed how long it took for a rubber stopper tied to 0.8 m of string from a rod to go through 30 revolutions while spinning it above our heads. The velocity must be constant at all times to have accurate results. We also added 5 washers after each trial to add weight and to see how the results have changed.

We needed:

• to calculate the time for 1 revolution
• speed (m/s), and
• speed^2 (m's)^2

There are two graphs needed to be handed in; force vs speed and force vs. speed^2 along with the questions attached to the back of the worksheet. The lab write up is due tomorrow, so if you weren't in class today be sure to pick them up.

Take care, see you all tomorrow.
-- son.

I noticed that no one has blogged for a long time ... A week, actually? So I will blog for today's class because I can't remember that far back... Yesterday, however, the class was taken up by the spirit week event. Yay school spirit~

Anyway... In class, we went over the Chapter 7 Study Guide, Periodic Motion; CIRCULAR MOTION.
Answers: constant, changing, changing, constant, perpendicular, tangent, instantaneous velocity, length, direction, radius, centre, centripetal, directly, inversely, second, force, centripetal force, straight, and tangent.

That was the only paragraph we went over.

We then looked at the free body diagrams worksheet, you may refer to the "Free Body Diagrams-Circular Motion" slide uploaded by Ms K.

After that she wrote us an assignment to do from the "duck book" textbook.
Which was to read p. 202-206, and do problems 1-5 on page 206.
She also wrote - Note: derivation of formula on p.205

If you didn't bring a textbook home, here's one question you can try:
The outer edge of a 120-mm-diameter CD-ROM experiences an acceleration of 1.6 m/s². What is the speed of the CD-ROM?

Reading the textbook would really help, because it stated that
V = d/t (velocity equals distance over time)
can be modified to
V = c/t (velocity equals circumference over time).
And since C = 2πr (circumference equals two times pi times radius), therefore,
V = 2πr/t

So that's all we did in class. I believe our catapult projectile motion project has been pushed to Thursday because of the talent show tomorrow. Yay~

Next scribe is sonson. :)

Free Body Diagrams-Circular Motion

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