Paraglider acceleration problem

[spoonthrower]

A paraglider is flying horizontally at a constant speed. Assume that only two forces act on it in the vertical direction, its weight and a vertical lift force exerted on its wings by the air. The lift force has a magnitude of 1900 N. For both questions, take the upward direction to be the +y direction.
(a) What is the magnitude and direction of the force that the paraglider exerts on the earth?

This correct answer is 1900 N upwards. I need help with the next part.

(b) If the lift force should suddenly decrease to 1000 N, what would be the vertical acceleration of the glider?
m/s2

 

[gunblaze]

If lift force decreases to 1000N, what will be the resultant force on the body now? What relationship does resultant force and acceleration have?

 

[spoonthrower]

so would that mean the skydiver falls with a force of 900 N downward? How do I get his acceleration from that because i don't know his mass. Help?