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| This text is meant to accompany class discussions. It is not everything there is to know about uniform circular motion. It is meant as a prep for class. More detailed notes and examples are given in the class notes, presentations, and demonstrations. See the links below. |
Click here for reading questions.
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| Conservation of Mass-Energy |
An atom with one proton is called Hydrogen. One proton and 2 neutrons is called "tritium." Its symbol is 3H. It mass is 5.00827 × 10-27kg. The mass of a proton is 1.6727 x 10-27kg. The mass of nuetron is 1.6750 x 10-27 kg. The mass of tritium does not equal the sum of its particles. |
| 1 proton |
(1)1.6727 x 10-27kg |
| 2 neutrons |
(2)1.6727 x 10-27kg = 3.3454 x 10-27kg |
| sum |
5.0181 x 10-27kg |
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The individual parts mass more than tritium atom by 0.0098 x 10-27 kg. Logic says these should match. It take energy to bind these three particle togetehr to create a tritium atom. In fact it take an amount of energy equal to teh mass differnce. This difference is refered to as the "mass defect." The mass defect is the binding energy.
Use E=mc2 to calculate the binding energy. In this case.
E = mc2
E = (0.0098 x 10-27 kg)(3.00x 108m/s)2
E = 8.85 x 10-13 Joules |
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