A long wire stretches along the x axis and carries a 4.0 {rm A} current to the right left( +x right). The wire is in a uniform magnetic field {bf{vec B}} = left( 0.22{bf i} -0.39{bf j} + 0.25{bf k} right),{rm T}. Determine the {rm x}-component of the force on the wire per {rm cm} of length.