Momentum question help?

The velocity change is Δv = Δp/m = (-2i+3j)/0.5 = (-4i+6j). The old velocity is v_old = 10,-6; v_new = 6, 0. So tha angle starts at atan2(10, -6) = 2.1 rad. The new angle is 0 rad. The deflection is -2.1 rad. (-121°)