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Q: A Positron has the same mass, but opposite charge to an electron. A Positron and electron are orbiting around each other separated by 1μm, in a stable circular orbit about their centre of mass, as a result of electrostatic attraction. Calculate the period.

Therefore:

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mi>b</mi><mo>&#xB1;</mo><msqrt><msup><mi>b</mi><mn>2</mn></msup><mo>-</mo><mn>4</mn><mi>a</mi><mi>c</mi></msqrt></mrow><mrow><msup><mn>2</mn><mn>4</mn></msup><mi>a</mi></mrow></mfrac><mo>&#xA0;</mo><mo>&#xA0;</mo><msup><mrow><mo>&#xA0;</mo><mn>2</mn></mrow><mn>42</mn></msup><mo>&#xA0;</mo><mn>443</mn></math>




Fc=Fe

mr2 = kq1q2r2


We can further decompose and write it in terms of the time period T:


=2T


Therefore, our equation becomes:


mr2T2= kq1q2r2


mr42T2=kq1q2r2


42mr3kq1q2=T2


42mr3kq1q2=T


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