Edits to “Statement”, “Solution”, “Answer”
en/7.4.35.md
+44 −4
| @@ -1,15 +1,55 @@ | |||
| ### Statement | |||
| − | $7.4.35.$ What is the period of small vibrations of four charged bodies connected by | ||
| + | $7.4.35.$ What is the period of small vibrations of four charged bodies connected by | ||
| + | identical filaments of length l and moving as shown in the figure? Mass and | ||
| + | charge of the body m and q. | ||
| − |  | ||
| + | |||
| + | |||
| ### Solution | |||
| + | The diagonal | ||
| + | $$ | ||
| + | d=l\times\sqrt(2) | ||
| + | $$ | ||
| + | $$ | ||
| + | d1=d+x | ||
| + | $$ | ||
| + | $$ | ||
| + | F=k×q×q/(d1×d1) | ||
| + | $$ | ||
| + | $$ | ||
| + | dF/dx=-2k×q×q/(d-x)\wedge3 | ||
| + | $$ | ||
| − |  | ||
| + | k' is stifness of spring | ||
| + | $$ | ||
| + | k'×dx=dF | ||
| + | $$ | ||
| + | $$ | ||
| + | k'=2×k×q×q×dx/d\wedge3 | ||
| + | $$ | ||
| + | But the spring located between 2 object.We need period one of them | ||
| + | |||
| + | The period formula | ||
| + | $$ | ||
| + | T=2×\Pi×\sqrt(m/K) | ||
| + | $$ | ||
| + | But the spring is between 2 object | ||
| + | We need use half of spring | ||
| + | so | ||
| + | $$ | ||
| + | K=k'×2 | ||
| + | $$ | ||
| + | The period is | ||
| + | $$ | ||
| + | T=2×\Pi×\sqrt(m×d\wedge3/(4×k×q×q)) | ||
| + | $$ | ||
| + |  | ||
| #### Answer | |||
| $$ | |||
| − | T=2 | ||
| + | T=2×\Pi×\sqrt(4×\Pi×\varepsilon×m×l×l/\sqrt(2)×q×q) | ||
| $$ | |||
| @@ -1,15 +1,55 @@ | |||
| ### Statement | ### Statement | ||
| $7.4.35.$ What is the period of small vibrations of four charged bodies connected by |
$7.4.35.$ What is the period of small vibrations of four charged bodies connected by | ||
| identical filaments of length l and moving as shown in the figure? Mass and | |||
| charge of the body m and q. | |||
|  | ||
| ### Solution | ### Solution | ||
| The diagonal | |||
| $$ | |||
| d=l\times\sqrt(2) | |||
| $$ | |||
| $$ | |||
| d1=d+x | |||
| $$ | |||
| $$ | |||
| F=k×q×q/(d1×d1) | |||
| $$ | |||
| $$ | |||
| dF/dx=-2k×q×q/(d-x)\wedge3 | |||
| $$ | |||
|  | k' is stifness of spring | ||
| $$ | |||
| k'×dx=dF | |||
| $$ | |||
| $$ | |||
| k'=2×k×q×q×dx/d\wedge3 | |||
| $$ | |||
| But the spring located between 2 object.We need period one of them | |||
| The period formula | |||
| $$ | |||
| T=2×\Pi×\sqrt(m/K) | |||
| $$ | |||
| But the spring is between 2 object | |||
| We need use half of spring | |||
| so | |||
| $$ | |||
| K=k'×2 | |||
| $$ | |||
| The period is | |||
| $$ | |||
| T=2×\Pi×\sqrt(m×d\wedge3/(4×k×q×q)) | |||
| $$ | |||
|  | |||
| #### Answer | #### Answer | ||
| $$ | $$ | ||
| T=2 |
T=2×\Pi×\sqrt(4×\Pi×\varepsilon×m×l×l/\sqrt(2)×q×q) | ||
| $$ | $$ | ||