Thursday, October 23, 2008

Mole Day !

Hello physics lovers :)

Here's a summary of today's class!

First we corrected the Chapter 7 Study Guide (7.2 Periodic Motion Circular Motion) that was given the previous day. Here are the the answers:

If an object is moving with uniform circular motion, the speed is constant. Velocity is changing because the direction is changing. In uniform circular motion, the radius of the path is constant. The velocity is perpendicular to the radius and tangent to the circular path. Any vector that is tangent to the circle represents the instantaneous velocity at that point. All such vectors will have the same length, but different directions. The vector that represents acceleration is in the direction of the radius, pointing toward the center of the circle. Centripetal acceleration points toward the center of the circle. It is directly proportional to the square of the speed and inversely proportional to the radius of the circle. According to Newton's 2nd law, centripetal acceleration must be caused by a(n) force that acts toward the center of the circle. The force that causes centripetal acceleration is called centripetal force. If this force disappears, the object in uniform circular motion will travel on a path it is a(n) straight line tangent to the circle.

After that we corrected the Free-Body Exercise: Circular Motion,
here are the answers:




Then Ms. K handed out notes on Centripetal and Centrifugal Forces.

Centripetal force is the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation. For example the car going around a curve there must be friction to provide the required centripetal force, if the force of friction is not great enough, skidding will occur.

Centrifugal force
is the apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation like the the clothes being force against the wall of the washing machine.

We also got a hand out on Frames of Reference, that we read while Ms. K got the television for a video on Circular Motion.

Here are some videos I found on You Tube that I hope will help!

Look who I found, MR. SAME SAME !



It's Bill Nye the Science Guy!

PART ONE:


PART TWO:


PART THREE:



I hope this helped! Sorry for the late blog.
The next scribe for tomorrow is Richard,
you said to pick you.. you have all weekend :)


Goodnight Everyone!

1 comment:

Ms K said...

Great post. really enjoyed Bill Nye, the science guy.