A^_("pi-minus") particle, which has charge^_e, is at location5.0010^-9,-2.0010^-9,-7.0010^-9m. What is the electric field at location<-3.0010^-9,3.0010^-9,3.0010^-9> m, due to the^_particle? =

An antiproton (same mass as the proton, charge^_e) is at the observation location. What is the force on the antiproton, due to the^_? =