PASCO PS-2006 GLX Power Amplifier - Manual (Page 22)

®
P S - 2 0 0 6 G L X P o w e r A m p l i f i e r S a m p l e E x p e r i m e n t s : S t a n d i n g W a v e o n a S t r i n g
20
3. If necessary, use the arrow keys to select the entire data set, or the
part of the data set that you want the fit applied to.
According to equation 5, the slope of the best-fit line is equal to
. Measure the length of the string (from the string vibrator
to the pulley), the mass of one meter of string, and the hanging mass.
Calculate
and compare it to the actual slope.
Further Study: Force versus Frequency
1. Start a file on the GLX. (Go to the Data Files screen, press
and select New File.)
2. Connect a force sensor to the GLX.
3. Hang the force sensor in place of the hanging mass. Let the force
sensor hang freely with just its own weight (Figure 18).
4. Set up the GLX for manual sampling without hand-entered data:
a. Press + to open the Sensors screen.
b. Press to open the Mode menu.
c. Press the down arrow key to highlight Manual and press .
The Data Properties box opens.
d. Press (No Data).
5. In the Output Screen, adjust the output frequency and amplitude to
produce a second-harmonic standing wave (two segments).
6. Set the frequency step size to 10 Hz.
7. Press . The flashing icon appears to indicate that the GLX is
ready to record manually triggered points.
8. Press to record a data point.
9. Increase the output frequency by 10 Hz (press ).
10. Pull the force sensor to increase the tension of the string until it res-
onates in the second harmonic again.
11. Press to record another data point.
12. Repeat steps 9 through 11 for up to 5 or 6 data points. Adjust the
output amplitude as needed.
13. When you have finished collecting all data, press to end the
data run.
14. In the Calculator screen, create a calculation to give the square root
of force (Figure 19a).
15. Compare the graphs of f versus F and f versus . Which one
shows a linear relationship?
F
µ ⁄
2L
( ) ⁄
F
µ ⁄
2L
( ) ⁄
Figure 18: Force Sensor
F4
F4
F1
F2
a
b
c
Figure 19: (a) calculation
(b) f vs. F (c) f vs.
F
F
+
F