Rotational Inertia A. Einsteen
Aim: (This should be a clear statement of the purpose for doing the lab - that is, what outcome are you expecting.)
To measure the rotational inertia of a collection of disks in two ways: first by measuring their dimensions and using the theoretical expression for the rotational inertia of disks, and secondly by analyzing dynamics involved in accelerating the disks by a hanging mass. The effect of friction will also be quantified.
Procedure: (I do not want a repetition of all the steps in the procedure given in the lab. Here is the place to draw diagrams of apparatus or objects that will clarify your data and results, or to put in equations or theory that you want to remember.)
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Data: (You should think ahead to the measurements you will be making and design a table that will clearly and conveniently hold the data you collect. You can put "reduced data" in this table - that is, you can put in data that has been derived by a calculation, if it makes sense to show it there.)
| Disk | Width (m) | Diameter (m) | Mass (kg) | Rot. Inertia (kgm2) |
| Disk 1 | ||||
| Disk 2 | ||||
| Disk 3 | ||||
| Disk 4 |
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Itheory = xxxx ± xx |
M = r Vol = 1/4 p wD2r, and I = 1/2 MR2 = 1/8 MD2
DI/I = DM/M + 2DD/D= Dw/w + 4DD/D
| D | d | t | tav±Dtav | a | I±DI | |
| Disk ? | ||||||
| Disk ? | ||||||
a = 2d/t2 and I = ¼mD2(g/a - 1)
DI/I = 2DD/D + Da/a= 2DD/D + (Dd/d + 2Dt/t)
| Number of Revs | Time to stop | afriction |
| Trial #1: | ||
| Trial #2: | ||
| Trial #3: |
afriction = 4pN/t2
Analysis/Results: (Here is where you answer questions and show error propagation)
Error calculations:
Question 1: ...
Question 2: ...
| Itheory±DItheory | Iexpt±DIexpt | Iexpt±DIexpt (with friction correction) | Percentage Error |
Number line:
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Conclusion: (This section should reflect the "Aim" of the lab directly.)