a sack is in contact with both the base and the vertical back of an excavator scoop. the excavator is moving forward at constant speed in a straight line. make separate sketches showing the forces acting on the sack and the scoop.
ok the sketches aren't important, i just want to make sure i have all the forces correct. so for he sack i'm pretty sure that the vertical forces are its weight and the normal reaction from the scoop, while the horizontal forces would be the force exerted by the scoop and the normal reaction from the sack, is this correct?
however for the scoop i am less sure. there is the normal reaction exerted by the sack, the force from the excavator, but then what?