okay I'm not quite sure i know all of those abbreviations.
but i think the only forces acting on the small box is the force as it slides down the plane (from gravity) and the force from the ramp from it being pulled. the normal force cancels out with mgcos(theta) and there is no friction...
Homework Statement
A block of mass 2.1 kg is placed on a frictionless inclined ramp of mass 20.0 kg, with the angle θ= 31o as shown below.
http://s4.lite.msu.edu/res/msu/physicslib/msuphysicslib/09_Force_and_Motion/graphics/prob91_plane2.gif
Calculate the size of the net horizontal...