How do i calulate the kinetic energy and speed of a particle released form a beta decay reaction? for example, if i have Na -> Mg + e (i can't type in the atomic masses and numbers) Would i subtract the mass of Mg from Na ? m=m_Na-m_Mg =23.990961u-23.985042 =0.005937u then multiply that mass by 931.5 (b/c 1u=931.4MeV) E=0.005937*931.4 =5.5297MeV ^^^is that the kinetic energy, or is that the energy released? they are different right? does finding the kinetic energy involve something with the masses of daughters and masses of parents? Once i have found the correct energy would i just rearrange the equation E=1/2mv^2 to find the speed? Also, is the mass of, for exapmle, oxygen is 15.003065u, what is that is kg? what does u mean? and what is the mass of an electron in 'u'