Sunday, March 14, 2010 7:29:20 PM
"The sign is upside down." ummm... more than likely sideways, but definitely not upside-down. unless of course this is in fact the land of Escher.
Actually, as long as the the truck maintained a minimum acceleration, that's quite possible. Creating an x-y axis tangential to the slope, the y forces would be the normal force and the gravitational force going perpendicular into the slope. The x forces would be the forward force of the truck, the frictional force, and the x gravitational force. Thus, in order to go up the hill, the truck would simply need to maintain a massive acceleration to overcome the two resistant x forces.