I found these [experimental data](https://en.wikipedia.org/wiki/Tests_of_relativistic_energy_and_momentum#Bertozzi_experiment) on mass increase. > Data of the Bertozzi experiment show close agreement with special > relativity. Kinetic energy of five electron runs: 0.5, 1, 1.5, 4.5, 15 > MeV (or 1, 2, 3, 9, 30 in mc²). Speed: 0.752, 0.828, 0.922, 0.974, 1.0 > in c (or 0.867, 0.910, 0.960, 0.987, 1 in c²). - Do you know of any link where I can find more precise experimental data (say accurate to five digits) for mass increase? For example, in the above table, is 0.5 MeV a rounded figure for 0.511 MeV , the rest mass of an electron? supposing the latter, what is the exact mass increase, is it exacly one mass (+ the usual rest mass), so the total mass is 2.00000 $m_e$? And, if we give energy equal to 30 m(e) speed is surely not 1, what is the exact value? - At what speed/energy there is minimum agreement with the SR formula? according to the picture it is about 5-6 MeV, is this correct? - Can you also specify if "increased mass" means that the body exerts an increased (and exactly proportional) gravitational force? Does it mean that an electron with 1 GeV Ke exerts a pull equal to a proton?