Then the gravitational force on her should be equal to the air resistance, i.e. 500 N.
In fact, the woman is falling at constant velocity, 5 m/s. This means there is no acceleration on her. But Netwon's second law states that the resultant of the forces acting on the body is equal to the product between the mass and the accleration:
[tex]\sum F =ma[/tex]
But the acceleration is zero, so the resultant of the forces acting on the woman must be zero. Since only two forces are acting (the air resistance, upward, and the gravity, downward) and they are in opposite direction, they must have equal intensity in order to produce a net acceleration of zero, so they both have intensity of 500 N.
