18-Sept-2014 Modeling Friction Forces Lab #7

Purpose:
This lab was designed for us students to figure out the value of the static force of an object held against another object.

Materials:

• 1 wooden block with felt
• 3 wooden blocks
• Styrofoam cup with string attatched
• water
• "frictionless" pulley

 The basic set up of this lab is the pulley locked on the table with a string connecting the block and foam cup going through the pulley.

The way we do this lab is pour water into the cup little by little until the block moves slightly. Once it moves we measure the cup for mass. This way we can calculate the normal force and static friction.

 This part is with two blocks. (Be careful with spills)

Then three blocks. We do this one more time with four blocks.

With this table you can see all the masses of water and blocks along with there normal forces and max static friction.

By putting the max friction and the normal force on logger pro we were able to graph and create the best fit line. The best fit lines slope is our static friction (0.3019).

Purpose:
Next is to find the kinetic friction of the blocks stacked on top of each other and dragging it across the table using a sensor.

We did this four different times with different am amounts of blocks.

This is the data we collected along with the recorded values from logger pro.

This last graph shows the kinetic relation between all of the trial and with the slope of the trend line we are able to determine its kinetic friction (0.3957).

Purpose:
The last part of this lab we have to determine kinetic and static but at a high slope.

The first step is to find the slope in which the block barely starts to move. Once that is done we measure the angle (ours being 30.5).