How Do You Calculate Wave Properties in a String Experiment?

[charmedbeauty]

Homework Statement

During the experiment you will be collecting data similar to that in the table below. The experimental set up is the same as that described in your lab manual. Complete this table. Assume that the frequency is 50 Hz, and is known accurately.

this is the data given.

1 Loop (mm) =48.9 +/- 1.5
2 Loops (mm)=96.4 +/- 2.0
3 Loops (mm)=141.3 +/- 2.0

Hanging mass= 200 +/- 5 (g)

frequency = 50 Hz

Find

1)Wavelength with uncertainty (mm)

2)velocity m/s with uncertainty

3)Tension (N) with uncertainty

Homework Equations

The Attempt at a Solution

to find the wavelength

im guessing I should find the average length within the loops.

so...

48.9 + 96.4/2 + 141.3/3 =144.2

144.2/3 = 48.1

λ= 2* (48.1)

λ= 96.1 (is this right??) →how would I find the uncertainty? is it just find λ with the largest value for the length and subtract λ with the smallest length and divide by 2?

v=fλ

v= 50(0.0961)

v= 4.807 m/s (is this right) → is the uncertainty just the uncertainty in λ?

T = mg

T = 0.2 (9.8)

T= 1.96N and uncertainty in T is I'm guessing the uncertainty in mass = 0.005 are these the right units (kg).

Thanks.

 

[Simon Bridge]

im guessing I should find the average length within the loops.

as good as any

λ= 96.1 (is this right??)

that what you calculated

how would I find the uncertainty? is it just find λ with the largest value for the length and subtract λ with the smallest length and divide by 2?

No - you derive it from the uncertainties in the individual measurements.

eg. if x is the measurement and s is the uncertainty then the uncertainty on ax is as (where a is a constant) and so on. You'll have these rules written down somewhere.

I think that actually answers all you questions.