Awoman falls to the ground while wearing a parachute. the air resistance on the parachute of the parachute is 500n. if the woman falls at a constant rate of 5m/s, then the gravitational force on her is

The fact that the woman falls at a constant velocity means its acceleration is zero. 
For Newton's second law, the resultant of the forces acting on a body is equal to the product between the mass m of the body and its acceleration a:

In our problem, the acceleration is zero, so the resultant of the forces should be zero as well.

Only two forces are acting on the woman: the air resistance R (upward, 500 N) and the weight W (downward). The resultant of these two forces is zero, so


and since the air resistance R is 500 N, then the weight (the gravitational force) of the woman is 500 N as well.