Question

When a trebuchet counterweight is hoisted by soldiers, what form of energy is

Answer 1

10. A safe place to use the trebuchet would be away from other buildings and people. A good example of a place would be a large field with no nearby structures. 
14. Many factors need to be kept consistent throughout the experiment. One example of a variable that would need to be consistent is the weight and size of the projectile. 
15. It is important to do many trials so that you can make sure that the results of each trial are nearly the same. If they are all vastly different, then it means that something has gone wrong. 

Sorry I was only able to answer a few questions, but I hope these few answers help! :) 

Answer 2

4. What force must be overcome to lift the counterweight?

Weight and/or gravity.