A spacecraft thruster exerts a force on space debris given by FSD=k^+4^−2k^N, where k is a positive constant.
(i) If the debris exerts a reaction force on the spacecraft whose magnitude is ∣FDS∣=9N, find the value of k.
(ii) Write the full vector for the force on the spacecraft, FDS.
(iii) Show that the two forces obtained are collinear but oppositely directed.