A proton is initially at rest. At time t = 0, O 1. (1, 0,0) it is accelerated upward with an acceleration of 2.8 x 1018 m/s2 for a very short time . We O 2. (-1, 0, 0) make observations at location A, 12 m from the proton as in the figure below. 3. (0, 0, 1) a = 2.8 x 1018 m/$2 4. (0, 1, 0) 5. (0, -1, 0) . Proton A F-- ---12 m - -- -- 6. (0, 0, -1) Take the + direction to be toward the right, the +y direction to be upward, and the +z direction to be out of the page (toward you). What is the direction of the radiative elec- tric field at location A at time t = 4 x 10-s? Choose the unit vector corresponding to this direction