hi there! I`m stuck on the following two questions and I hope you could help me :) I´m given the kinetic energy of a particle. How am I supposed to calculate its velocity? there´s no mass of rest, no total energy, just the kinetic energy. 2. While trying to calculate the time dilation in the inertial frame of a satellite, it´s velocity appears too small to experience relativistic effects. The satellite´s orbit´s radius around the Earth is 20.10^6m, which gives a velocity of v=1454,4 m/s (with respect to Earth´s angular velocity). Now plugging it into the Lorentz factor "gamma" it appears to be really insignificant! Am I doing something wrong there? thanks a lot in advance!