I know I'm a bit late but just in case you still need some of the answers.
1: Oxygen
2: Change in shape
3: Water breaking down into hydrogen and oxygen
4: I think it's Milk but I might be wrong.
I might be wrong about some of them, sorry it's not much.
C) total linear momentum of the ball and cannon is conserved.
Basically it happens that in the beginning before there is a momentum acting on the two bodies, these are a unique system. Here the total momentum of the System is 0. However, when the positive momentum of the cannonball is added, the system will be immediately affected by a negative momentum which will pull back the cannon. Could this be extrapolated as a condition of Newton's third law.
Answer:
My best friend lol cuz since quarantine i didn't see her
Answer:
Part a)

Part B)

Part C)

Explanation:
Part A)
As we know that ball is hanging from the top and its angle with the vertical is 20 degree
so we will have






Part B)
Here we can use energy theorem to find the distance that it will move




Part C)
At terminal speed condition we know that



