Правка разделов «Statement», «Solution», «Answer»
en/3.3.31.md
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| ### Statement | |||
| − | $3.3.31.$ [Insert the problem statement] | ||
| + | $3.3.31.$ To measure small amplitudes of oscillations of a diaphragm making harmonic vibrations of high frequency $\omega$, a ”hammer” connected in an electrical circuit with a diaphragm and a telephone is used. The hammer of mass $m$ is pressed against the diaphragm with a force that is adjusted by a micrometer screw. When the contact of the hammer with the diaphragm is interrupted, the current in the circuit is interrupted and a rattling can be heard in the telephone. Determine the amplitude of the vibrations if the rattling begins when the force with which the hammer presses the diaphragm reaches the value $F$. | ||
| + |  | ||
| + | |||
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| ### Solution | |||
| − | 213 | ||
| + | This promlem is analogous to the previous one ([$3.3.30$](/en/3.3.30); if anything, look at the solution of the mentioned problem in russian). We can write for the hammer (projection onto the axis of oscillations) | ||
| + | $$ | ||
| + | F-N=ma, | ||
| + | $$ | ||
| + | |||
| + | where $N$ is the normal reaction force of the diaphragm, $a$ is the acceleration of the hammer. | ||
| + | |||
| + | The diaphragm perform harmonic oscillations, thus | ||
| + | |||
| + | $$ | ||
| + | a=\omega^2A\sin\omega t, | ||
| + | $$ | ||
| + | |||
| + | where $A$ is the oscillation amplitude of the diaphragm, $t$ is time period. | ||
| + | |||
| + | From the previous equations we can obtain | ||
| + | |||
| + | $$ | ||
| + | N=F-m\omega^2A\sin\omega t. | ||
| + | $$ | ||
| + | |||
| + | If the value of $F$ is larger than $m\omega^2A$, then $N>0$ and there will be no the rattling (since $-1\leqslant\sin\omega t\leqslant1$). The rattling begins, when | ||
| + | |||
| + | $$ | ||
| + | F=m\omega^2A | ||
| + | $$ | ||
| + | |||
| + | and therefore | ||
| + | |||
| + | $$ | ||
| + | A=\frac{F}{m\omega^2}. | ||
| + | $$ | ||
| + | |||
| + | |||
| #### Answer | |||
| − | [Insert a concise answer or boxed result] | ||
| + | $$ | ||
| + | A=\frac{F}{m\omega^2}. | ||
| + | $$ | ||
| @@ -1,11 +1,49 @@ | |||
| ### Statement | ### Statement | ||
| $3.3.31.$ [Insert the problem statement] | $3.3.31.$ To measure small amplitudes of oscillations of a diaphragm making harmonic vibrations of high frequency $\omega$, a ”hammer” connected in an electrical circuit with a diaphragm and a telephone is used. The hammer of mass $m$ is pressed against the diaphragm with a force that is adjusted by a micrometer screw. When the contact of the hammer with the diaphragm is interrupted, the current in the circuit is interrupted and a rattling can be heard in the telephone. Determine the amplitude of the vibrations if the rattling begins when the force with which the hammer presses the diaphragm reaches the value $F$. | ||
|  | |||
| ### Solution | ### Solution | ||
| 213 | This promlem is analogous to the previous one ([$3.3.30$](/en/3.3.30); if anything, look at the solution of the mentioned problem in russian). We can write for the hammer (projection onto the axis of oscillations) | ||
| $$ | |||
| F-N=ma, | |||
| $$ | |||
| where $N$ is the normal reaction force of the diaphragm, $a$ is the acceleration of the hammer. | |||
| The diaphragm perform harmonic oscillations, thus | |||
| $$ | |||
| a=\omega^2A\sin\omega t, | |||
| $$ | |||
| where $A$ is the oscillation amplitude of the diaphragm, $t$ is time period. | |||
| From the previous equations we can obtain | |||
| $$ | |||
| N=F-m\omega^2A\sin\omega t. | |||
| $$ | |||
| If the value of $F$ is larger than $m\omega^2A$, then $N>0$ and there will be no the rattling (since $-1\leqslant\sin\omega t\leqslant1$). The rattling begins, when | |||
| $$ | |||
| F=m\omega^2A | |||
| $$ | |||
| and therefore | |||
| $$ | |||
| A=\frac{F}{m\omega^2}. | |||
| $$ | |||
| #### Answer | #### Answer | ||
| [Insert a concise answer or boxed result] | $$ | ||
| A=\frac{F}{m\omega^2}. | |||
| $$ | |||