Laboratory Guide: Circular Motion
Physics - 11th Grade
Néstor Forero Alcalá IED
Objective:
In this laboratory, you will investigate the circular motion of an object using
the interactive PhET simulation "Rotation: Circular Motion." You will
explore how the distance from the axis of rotation, angular velocity, and
other parameters affect circular motion. Additionally, you will calculate the
period, frequency, centripetal acceleration, and centripetal force
from the data obtained.
Materials:
Computer with internet access.
Web browser (recommended: Chrome or Firefox).
Access to the PhET simulation: Circular Motion Simulation.
Calculator.
Notebook for recording data.
Procedure:
1. Access the Simulation
Open the following link in your browser: Circular Motion Simulation.
Click on "Start Simulation."
Ensure that the simulation loads completely.
2. Simulation Setup
Choose the "Experiment Mode" where you will see a rotating disk or
wheel.
In the simulation, you can adjust the following parameters:
o Angular Velocity (in degrees per second, °/s): Adjust the
rate at which the object rotates.
o Distance (Radius) from the axis of rotation (in meters):
Change the distance from the object to the axis of rotation.
o Rotation Angle: Observe how the angle changes over time.
3. Data Collection
Perform the following experiments to collect the necessary data:
Experiment 1: Period and Frequency Calculation
Select a radius r (e.g., 0.5 m, 1.0 m, 1.5 m) and set an angular
velocity of your choice.
Start the rotation and measure the time (T) taken for one
complete revolution.
Record the time for at least three trials and calculate the average
period (T).
Use the formula to find the frequency (f): f=1Tf = \frac{1}{T}f=T1
where:
o TTT is the period (time for one full revolution, in seconds).
o fff is the frequency (revolutions per second, in Hz).
Experiment 2: Relationship Between Radius and Circular Motion
Change the radius (r) and measure the time for one complete
revolution again.
Record data for at least three different values of radius and
observe how the period and frequency change.
4. Calculations
Convert Angular Velocity to Radians per Second
Since the simulation provides angular velocity in degrees per second, you
need to convert it to radians per second using:
ω (rad/s)=ω (°/s)×π180\omega \ (\text{rad/s}) = \omega \ (\text{°/s}) \
times \frac{\pi}{180}ω (rad/s)=ω (°/s)×180π
where ω\omegaω is the angular velocity in radians per second.
Centripetal Acceleration (aca_cac)
ac=ω2ra_c = \omega^2 rac=ω2r
where:
ω\omegaω = angular velocity in radians per second.
rrr = distance from the axis of rotation (radius in meters).
Centripetal Force (FcF_cFc)
Fc=m⋅acF_c = m \cdot a_cFc=m⋅ac
where:
mmm = mass of the object (use an assumed value for analysis).
aca_cac = centripetal acceleration calculated previously.
Reflection Questions:
1. How does increasing the radius affect the period and frequency?
2. What happens to centripetal acceleration when you increase the
angular velocity?
3. What is the relationship between period, frequency, and angular
velocity?
4. How does the centripetal force change when you modify the radius?
5. Why is centripetal acceleration necessary for circular motion?
Analysis of Results:
Organize your data in a table to compare period, frequency, and
centripetal acceleration.
Use graphs to visualize relationships such as:
o Period vs. Radius.
o Centripetal Acceleration vs. Angular Velocity.
Compare your results with theoretical formulas to verify their
accuracy.
