PASCO ME-9821 Centripetal Force Pendulum User Manual

Page 10

Model No. ME-9821

Centripetal Force Pendulum

Experiment 2: The Effect of Radius on

Centripetal Force

In the following experiment, you will examine the effect of the
independent variable radius on centripetal force (while keeping the
mass constant).

Note: Follow the software setup instructions described on pages 5-6 of
this manual.

1. Move the clamp-on mass to a higher position on the rod (to change the

radius).

2. Tare the Force Sensor with the pendulum rod straight down at rest

(the zero position). Use a data collection software, such as
DataStudio, to verify zero force.

3. With the pendulum hanging straight down (zero position), click the

Start button. (Do not hold or move the pendulum during the zero!)

4. After about two seconds (to ensure a zero), rotate the pendulum

through 180 degrees and let it go.

5. With your hand, catch the pendulum after it falls back to the zero

position and immediately click the Stop button.

6. Using your data collection software, perform three separate runs

(each at a different radius) and record your results for each in Table
2a.

7. In your data collection software, make a graph of force vs. angular

position. Note the angle at which the force becomes zero. Does
this angle change or stay the same with a longer radius?

Table 2a

* Record the radius from the center axis of rotation to the center point
of the mass.

Trial

Radius of
Pendulum*
(m)

Angle at which the
Force=0 (degrees)

Note: Moving the pendu-
lum without an adequate
zero reading in DataStudio
will introduce error in your
readings. Always tare the
Force Sensor and watch
for a zero reading before
rotating the pendulum.