Pulses and Standing Waves
Obj:
Predict the velocity of a transverse wave based on the physical properties of long spring.

Materials: balance, Newton scale, spring, timer
Data, Methods, & Analysis

1. Mass of spring ___________kg
2. Length of spring ___________m
3. Tension (T) applied to spring __________ N
4. Calculate the velocity of the wave pulse in the spring using the equation where D is mass / length (kg/m)
vcalc = _______________m/s
5. Measure the velocity of the wave pulse in spring:

length L of spring _____________m number of lengths traveled = 5
total length traveled by pulse (L x 5) ___________m

Time 1______s Time 2______s Time 3______s Time4______s

Average time _________s

v = total distance / ave. time v = _________m/s
6. % error using calculated velocity as accepted. ______________%
7. Measure the velocity of waves from observed frequencies and wavelengths. [v = f
8] (Table below)
Length of spring ___________m

 Picture #Waves 8 (meter) Time(10) Period T freq f Velocity m/s (f x 8 ) .5 1 1.5 2.0 2.5

8. Calculate the average velocity from the table and compare with the calculated velocity in No. 4 above.
9. Plot the
8 (y-axis) vs Period (T). Calculate the slope. What does the slope represent?
10. What changes occur with wavelenght and frequency in the data table? velocity?
11. If the tension T were increased by a factor of 2, by what factor would the velocity of the pulse be change?
12. If the velocity was to be increased by a factor of 2, by what factor would the tension have to be increased?

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