Answer
See the detailed answer below.
Work Step by Step
a) See the figures below, and recall that: $F_n\rightarrow$ Normal force. $F_G\rightarrow$ Gravitational force (the weight of the object). $F_{\rm thrust}\rightarrow$ Thrust force. $D\rightarrow$ Drag force due to friction or air resistance.
b) The acceleration here is zero since the net force in both directions $x$ and $y$ is zero.
c) The direction of the speed is toward the thrust force, as we see in the figure below, and it is a constant velocity.
d) A modified motorcycle moves on a horizontal surface at a constant velocity toward the right.
