Purpose
The purpose of this lab was to compare mass vs. radial force as objects of different masses swing in a pendulum.
Theory
The pendulum swings in a circular motion so the centripetal force of the bob can be measured. The diameter of the bob can be measured and divided in half for the radius. To find the mass needed for the equations, the mass of the bob and rod are measured together. Radial force and velocity are both measured on data studio. The forces can be summed to find the calculated radial forces.
Experimental Technique
Procedure:
We set up the pendulum on the desk with the bob hanging straight down. Then we set up the photogate sensor around the bob and aligned it to get an accurate measurement. After hooking up the wires to the computer, we let the pendulum swing and data studio measured velocity and radial force.
After each data set, the mass the was increased by 50 grams to see how it would affect the measurements. We found that the measurements were linear to the amount of mass we added. That means as mass increases, so does velocity and radial force.
We set up the pendulum on the desk with the bob hanging straight down. Then we set up the photogate sensor around the bob and aligned it to get an accurate measurement. After hooking up the wires to the computer, we let the pendulum swing and data studio measured velocity and radial force.
After each data set, the mass the was increased by 50 grams to see how it would affect the measurements. We found that the measurements were linear to the amount of mass we added. That means as mass increases, so does velocity and radial force.
Data and Analysis
The table shows the raw data measurements we made for the the lab.
This graph shows the velocity and acceleration over a period of time of the bob on the pendulum. This was done in data studio.
This is the graph that shows the linear relationship between mass and force. As mass increases, the force also increases.
Example Equation
T = 10.12N
Conclusion
This lab was successful in determining the centripetal forces of a bob in swinging in a pendulum. Things that affect the centripetal force as it swings is the tension in the rod and the force due to gravity. Reasons for possible error between the measured and calculated values are from different starting positions of the bob and having pushes the bob slightly forward when releasing it. A way to fix this would be to mark exactly where to start the bob and carefully release it so no extra force is added to it. Adding different masses to the bob caused the velocity to increase at a linear rate. The first measurement with 106.1g had a velocity of 1.18m/s while the last measurement which had a weigh of 206.1 g had a velocity of 1.42m/s.
References
Boyle, J., & Giancoli, D. (1998). Study guide: Physics, principles with applications, fifth edition. Englewood Cliffs, N.J.: Prentice Hall.
Centripetal Force Lab - Pendulum Form. (n.d.). Retrieved December 7, 2015, from http://www.cbakken.net/weblabs/centforce.html
Online Equation Editor. (n.d.). Retrieved December 7, 2015, from http://www.homeschoolmath.net/worksheets/equation_editor.php
Centripetal Force Lab - Pendulum Form. (n.d.). Retrieved December 7, 2015, from http://www.cbakken.net/weblabs/centforce.html
Online Equation Editor. (n.d.). Retrieved December 7, 2015, from http://www.homeschoolmath.net/worksheets/equation_editor.php