Im about to the math for this right now.
1. By Newton's second law,
<em>F</em> = <em>m</em> <em>a</em>
so the slope of the line would represent the mass of the object.
2. If all the forces are balanced, then the object is in equilibrium with zero net force, which in turn means the object is not accelerating. So the object is either motionless or moving at a constant speed.
