11-17

November 17, 2008

Today’s physics class began with a graded daily question:

Draw a free body diagram showing the forces acting on the block and cylinder below. Don’t forget to draw arrows proportionally and label each force.

Answer shown here: http://canvaspaint.org/59ce.png

Pointers: Make sure that the length of the arrows that represent the gravitational force and the natural force are equal (vertical) Make sure that the length of the arrows that represent the kinetic friction force and the natural force are equal (horizontal)

Then we read through the lab that we picked up as we came into class titled, “The Force of Friction- What a Drag!”

In this lab we experiment to find out how different surfaces affect the amount of friction that is applied to an object. Using a force scale, we measure the amount of force needed to start an object in motion and also the amount of force needed to keep an object in motion. The objects we use are- a block with sand paper on the bottom, a block with foam on the bottom, and a block with nothing on the bottom.

So far my group has observed that it takes the __most__ force to start the block with foam on the bottom, and then the block with sandpaper, and then the block with nothing.

Things to keep in mind during this lab are: - Zero force scale - Clean surfaces - 1 kg mass - Drag slowly - Slide scale horizontally

We will continue to work on this lab tomorrow.

Reminder: Test/ Reading Guide due Friday (with question mark)

Peace out class:)