Answer:
adapted from NOVA, a team of historians, engineers, and trade experts recreate a medieval throwing machine called a trebuchet. To launch a projectile, a trebuchet utilizes the transfer of gravitational potential energy into kinetic energy. A massive counterweight at one end of a lever falls because of gravity, causing the other end of the lever to rise and release a projectile from a sling. As part of their design process, the engineers use models to help evaluate how well their designs will work.
Explanation:
The answer is C. elastic potential energy
Answer:
The burden distance is 7 ft
Solution:
As per the question:
Specific gravity of package emulsion, 
Specific gravity of diabase rock, 
Diameter of the packaged sticks, d = 3 in
Now,
To calculate the first trail shot burden distance, B:
![B = [\frac{2SG_{E}}{SG_{R}} + 1.5]\times d](https://tex.z-dn.net/?f=B%20%3D%20%5B%5Cfrac%7B2SG_%7BE%7D%7D%7BSG_%7BR%7D%7D%20%2B%201.5%5D%5Ctimes%20d)
![B = [\frac{2\times 1.25}{2.76} + 1.5]\times 3 = 7.22](https://tex.z-dn.net/?f=B%20%3D%20%5B%5Cfrac%7B2%5Ctimes%201.25%7D%7B2.76%7D%20%2B%201.5%5D%5Ctimes%203%20%3D%207.22)
B = 7 ft
