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