PASCO ME-8089 Computer-Based Centripetal Force Accessory - Manual (Page 9)

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Model No. ME-8089 Centripetal Force Accessory
9
5. In DataStudio, click the Start button and watch the Force vs. Speed graph as the platform
speed decreases. When the speed falls below 2 radians/second, click the Stop button.
Analysis:
1. Explain the shape of the force vs. velocity graph.
2. Create a graph of Force vs. Speed Squared. Does the graph show a straight line? Why or
why not? Find the slope.
3. Calculate the theoretical slope for where the slope is mr. Calculate the slope
using your values of m and r. Calculate the percent (%) difference between the two
values.
Part II: Centripetal Force vs. Mass
In Part II, the radius and velocity are held constant as the mass is varied. Adding extra drilled
masses to the mass holder increases the mass of the system. Equal amounts of mass must
also be added to the “fixed mass” to balance the arm as it rotates. Centripetal force is directly
measured by the Force Sensor.
Perform several different data runs, each time varying the mass on the sliding and fixed mass
holders. (The mass holder is about 50 g. The mass can be varied from 50 to 250 g in 50 g
increments.) (Note: Keep the speed constant. A motor drive with power supply can be used
to ensure a constant speed. Otherwise, spin the platform with your hand above some set speed
and start recording. When the platform slows down below the set speed, stop recording.)
Use a graph or table to record the force at a set speed. Repeat the experiment for the other
masses and make an editable graph of the Force vs. Mass.
F mr
ω 2
=
Figure 1-2B: Adding mass
to a holder
“Fixed” Mass
Holder “Sliding” Mass
Holder
Rotating
Arm
Figure 1-2A: Free and Fixed
Mass Holders