(ii) Air resistance is said to be negligible in the question and since air resistance would be the only horizontal force acting on the jet, the horizontal force is also 0. (1 mark) This results in the horizontal component of the jet's velocity being constant. (1 mark)Tate's Tips- Don't forget that 0 force only means 0 acceleration. It DOES'NT mean that velocity is 0 too. However, if the object is at rest while no force acts then its velocity will be 0 but that is the only time 0 force= 0 velocity.