Originally Posted by greenstork
It does take more force to counteract the force of gravity and this increased use of force is necessary to propel one up a hill but as long as this uphill tromp goes at a constant rate in the same direction, there's no acceleration.
The increased work required to climb is called potential energy. Basically you need to put energy into an object to raise it against gravity. You get that energy back as kinetic energy when coming back down. If you shoot a bullet in the air at 1500 ft/s, it'll come back at the same velocity (well a little less due to air resistance)... that's why every now and then you see stories about someone being killed by a bullet shot into the air.
Originally Posted by greenstork
I do stand by my statement however, that going at the same speed around a turn or in a circle requires acceleration.
Oh man... you were doing so good until that last sentence
It's the same thing as riding up a hill except you're balancing friction, angular velocity and centripetal acceleration. What is changing is the direction of the velocity vector but its magnitude is still constant.