A Crate Is Sliding Down an Inclined Ramp at a Constant

Multiple Choice

A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s.The vector sum of all the forces acting on this crate must point

A) down the ramp.
B) up the ramp.
C) perpendicular to the ramp.
D) vertically downward.
E) None of the above choices is correct.