The syllabus says: “Explain the concept of a mass defect using Einsteins equivalence between mass and energy” How?
Mass dilation “What is mass dilation?” You can think of it as an accounting system that almost no-one uses anymore so you can forget about it and jump to the next topic. Or you can read on. Today, we talk only about the mass m of an object, and we regard m as constant. If you are travelling in the same frame as the object, and if you apply a force F, it accelerates at F/m. If it is travelling at speed v with respect to you, it has a momentum p = γmv where γ is the usual relativistic factor, (1-v2/c2)-1/2. Of course, if v is much less than c, γ is almost exactly one, so we regain the Newtonian expression. Now if we were to write the above equation as p = (γm)v then the term in parentheses could be regarded as a ‘dilated mass’, and that is what you will find in some old text books. The reason why mass dilation is no longer used in discussing relativity is because it is very confusing. In the original papers, Einstein himself did use the idea of a longitudinal mass that increased with spe
