Question regarding bullets and such. Consider a 4.5kg mass at 20m/s has 900 Joules, 90 Newtons. And a 2kg mass at 30m/s has 900 Joules, 60 Newtons. Perhaps I've got the figures wrong, but it doens't make a difference to my question really. On webpages dealing with ballistics, when discussing the bullet's energy, they give the Joules from the kinetic energy formula 1/2m*v^2. Now, it seems to me inappropriate to give the answer in Joules, when discussing what a bullet does. You might as well give it in BTUs or such. It's simply an amount whihc doesn't really describe much. Seems to me it should be given in Newtons. Why would they give the Joules rather than Newtons when discussing the matter? Shouldn't Force be used, to show what the bullet is actually doing?