You Are Riding on a Flat Train Car and Are

Multiple Choice

You are riding on a flat train car and are climbing up the side of a hay stack. You are half way up the stack and are maintaining a steady height. You and the stack are moving steadily along the straight tracks at constant speed. The net force on you is

A) downhill-toward the bottom of the front of the stack.
B) zero.
C) uphill-behind you.
D) horizontal-parallel to the tracks.