1. The problem statement, all variables and given/known data A proton (rest mass 1.67x10^-27 kg) has total energy that is 3.2 times its rest energy. What is: a) the kinetic energy of the proton (in joules) b) the magnitude of the momentum of the proton (in kg*m/s) c) the speed of the proton (in terms of the speed of light "c") 2. Relevant equations E(0) = m(0)c^2 where E(0) is rest energy, m(0) is rest mass and c is the speed of light (approximately 3.00x10^8 m/s) E = mc^2 where E is the total energy (im not too sure if thats the formula for total energy) and m is the relativistic mass p=mv where p is the momentum E^2 = (p^2)(c^2) + (m(0)^2)(c^2) Ke = E - m(0)c^2 where Ke is the kinetic energy 3. The attempt at a solution I found the rest energy E(0) = m(0)c^2 = 1.503x10^-10 and since my total energy = 3.2 times the rest energy, E = 3.2E(0) = 4.81x10^-10. And because E = mc^2, i can use the previously calculated value to find m which gave me m= 5.344x10^-27. I used these values and the equation E^2 = (p^2)(c^2) + (m(0)^2)(c^2)to find the momentum which gave me 1.603x10^-18, which is correct. But when i use the formula p = mv and rearrange it as v = p/m, i get 0.9999c m/s which according to my homework isn't correct. And also, when i use the equation Ke = E - m(0)c^2 to find the kinetic energy, i get 3.307x10^-10, which is also incorrect. I know it's long but a little help would be appreciated.