1. The problem statement, all variables and given/known data The region of space around a moving proton contains a. a gravitational field only. b. a magnetic field only. c. an electric field only. d. an electric, magnetic and gravitational field. e. an electric and magnetic field only. 2. Relevant equations (conceptual question) See below. 3. The attempt at a solution I know that both a magnetic field and an electric field apply to a dynamic particle, but I am unsure of the gravitational field. Does a gravitational field only apply to stationary particles? Thanks.