Answer: B
D makes no sense because energy is created so we can remove that. C also makes no sense because if energy is not created how did it get destroyed if there's no energy in the first place. This leaves us with a and B the correct answer is B because energy is created and cannot be destroyed.
Without air resistance, both balls reach the ground at the same instant.
Neither horizontal motion nor weight affects vertical motion.
Answer:
7557.875 J
Explanation:
Assumimg we need to find work done by the bullet on the gas
The work is found by integrating force over distance
W= 
For the force in this problem we have

= ![[14000x+10000x^2-21000x^3]_{0}^{0.65}](https://tex.z-dn.net/?f=%5B14000x%2B10000x%5E2-21000x%5E3%5D_%7B0%7D%5E%7B0.65%7D)
=7557.875 J