A skydiver of mass 80 kg falls vertically with a constant speed of 50 m s−1. The upward force
Acting on the skydiver is approximately
A. 0N. B. 80N. C. 800 N. D. 4000 N.

We won't simply give you the answer to this homework problem. But t get you started - I suggest you first draw a free body diagram with the forces that are acting on the skydiver's body. Then consider the fact that his velocity is constant - what does that mean regarding the net force acting on his body? Post back with your attempt at this and we'll help you along of you are still stuck.