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courses:phy101l:3 [2023/07/11 03:23] – asad | courses:phy101l:3 [2023/10/31 03:36] (current) – [4. Moment of inertia] asad | ||
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====== 3. Moment of inertia of a flywheel ====== | ====== 3. Moment of inertia of a flywheel ====== | ||
+ | [[https:// | ||
===== - Introduction and theory ===== | ===== - Introduction and theory ===== | ||
+ | $$ mgh = \frac{1}{2} m r^2 \omega^2 + \frac{1}{2} I \omega^2 + n_1 W $$ | ||
+ | |||
+ | $$ \frac{1}{2} I \omega^2 = n_2 W \Rightarrow W = \frac{I\omega^2}{2n_2} $$ | ||
+ | |||
+ | $$ I = \frac{2mgh - mr^2\omega^2}{\omega^2\left(1+\frac{n_1}{n_2}\right)} $$ | ||
+ | |||
+ | $$ \frac{\omega+0}{2} = \frac{2\pi n_2}{t} \Rightarrow \omega = \frac{4\pi n_2}{t} $$ | ||
+ | |||
+ | $$ h = 2\pi r n_1 $$ | ||
===== - Method and data ===== | ===== - Method and data ===== | ||
+ | {{: | ||
+ | |||
+ | Number of rotations before the mass falls, $n_1=$ | ||
+ | |||
+ | Radius of the axle, $r=[(a+vb)/ | ||
+ | |||
+ | ^ Mass [g] ^ $n_2$ ^ $t$ [s] ^ | ||
+ | | 1000 | | | | ||
+ | | 1500 | | | | ||
+ | | 2000 | | | | ||
+ | | 2500 | | | | ||
===== - Angular velocity ===== | ===== - Angular velocity ===== | ||
===== - Moment of inertia ===== | ===== - Moment of inertia ===== | ||
+ | Mean | ||
- | ===== - Discussion and conclusion ===== | + | $$ \mu = \frac{1}{N} \sum_{i=0}^{N-1} x_i. $$ |
+ | Standard deviation | ||
+ | |||
+ | $$ \sigma = \sqrt{ \frac{1}{N} \sum_{i=0}^{N-1} (x_i-\mu)^2}. $$ | ||
+ | |||
+ | The final result of an experiment is quoted as | ||
+ | |||
+ | $$ \text{ value } = \mu \pm \sigma. $$ | ||
+ | ===== - Discussion and conclusion ===== | ||
+ | - Why does the flywheel come to a stop? | ||
+ | - Why are the 4 measurements of moment of inertia different? | ||
+ | - When does the flywheel reach its maximum velocity? | ||
+ | - What does the standard deviation (numpy.std) of $I$ tell you? |
courses/phy101l/3.1689067388.txt.gz · Last modified: 2023/07/11 03:23 by asad