Force & Motion: Frictional Force
In this activity, use the Force Sensor to investigate static friction and kinetic (sliding) friction of felt and cork trays on an aluminum track. Discover which combination of materials -- felt and aluminum or cork and aluminum -- has greater friction. Investigate how the friction force between two surfaces changes as the two surfaces are pressed together ...
Students can quickly measure the peak of the graph, which represents the maximum static frictional force. Once the friction tray begins to move, the kinetic frictional force becomes evident, so that students can compare the two forces.
Using the Discover Friction Accessory with the Dynamics Track for consistent, repeatable results.
Lab Summary
Students will use the Force Sensor to measure the force of static friction and the force of kinetic (sliding) friction on felt and cork trays on an aluminum track.
They will investigate friction forces as the normal force on the trays is increased. From the relationships between the friction and normal forces, they will determine the coefficients of static and kinetic friction.
Theory
The frictional force is based upon the normal force and the coefficient of friction which itself is determined by how rough or smooth the two surfaces in contact are. The kinetic friction force (when the object is moving) is generally slightly less than the static friction force.
Downloads
- Computer-based lab (PDF, 712 KB) (709 KB, .pdf)
(student versions)
- Xplorer GLX-based lab (PDF, 832 KB) (831 KB, .pdf)
(student versions)
Method
Use a Force Sensor to measure the force on an object as it is pulled across different surfaces. Analyze the graph of force versus time to determine the frictional forces. Calculate the coefficients of static and kinetic friction.
Here's What You Need
U.S. Educator prices shown.
Required for computer-based lab: (See lab download for Xplorer GLX-based lab requirements, which may differ)
Probeware
PASPORT Force Sensor (PS-2104) - $110
Designed to measure both pulling and pushing forces. Uses range from collisions to tug-of-war. For use with PASPORT Interfaces.
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
Other Products
1.2 m PAScar Dynamics System (ME-6955) - $259
Equip your lab with carts and a high-quality 1.2 m aluminum track.
Discover Friction Accessory (ME-8574) - $39
Four plastic trays with unique surfaces (cork, felt, and 2 plastic) to use with dynamics carts and sensors.
Braided Physics String (SE-8050) - $22
This string is tough, resists stretching, and will not unravel. Provides 320 meters of string.
Ohaus Triple-Beam Balance (without Tare) (SE-8723) - $147
This Ohaus triple-beam mechanical balance (without tare) is accurate and easy to use. This balance has been a standard weighing instrument in student laboratories for decades.
Lab Manual
The computer-based activity is included in Explorations in Physics (PS-2810). The Xplorer GLX-based lab is included in Physics with the Xplorer GLX (PS-2826). Both manuals are complete with Teacher Information pages, student instructions and handouts, and sample data.
For your convenience, we offer bundles which provide the probeware for the
activities in the manual. For more, please see:
Computer-based
Physics Lab Manual and Bundles
Xplorer
GLX-based Physics Lab Manual and Bundles
