You place a box on a smooth and evenly-sanded wooden board. Raise ...

[kaid0807]

You place a box on a smooth and evenly-sanded wooden board. Raise one end of the board so that the angle increases. Eventually, the box starts to slide along the board. If you maintain this angle of the board, the box
  1.will move at constant speed along the ramp.
  2.will do none of these.
  3.will slow down and stop along the ramp.
  4.will speed up along the ramp.

Question 2

A heavy box is located in the center of the cargo hold of a train. There are no other boxes or items in the cargo hold and there are no straps holding the box down. The train accelerates along the track in the northward direction. The direction of the friction force exerted by the floor of the cargo hold on the box is
  1.upward.
  2.none; no friction force exists because the box is not sliding.
  3.to the north.
  4.to the south.

[mcni194]

Answer to Question 1

4

Answer to Question 2

3