This is a very clever and interesting exercise. I'm typing on a little telephone screen and it would take me a week to explain my reasoning, so I can only give my proposed answer. It's . . . 60 degrees above the horizon.
Flexability because when you are bendable you can bend in any direction and that's what flexablitity is
Efficiency = Mechanical advantage / Velocity Ratio:
0.60 = M.A./6
MA = 0.6 * 6 = 3.6
The mechanical advantage is 3.6
Mechanical advantage = Force out / Force in
3.6 = 3000/ Force in
Force in = 3000/3.6
Force in = 833.33 N
Answer: 833.33N
