UTexas HW14: PV Diagrams #2

Dr. Winters said she would put up how to do it but this is my last question and i dont really wish to leave this blank so... can anyone that actually got the answer right explain how to get it...

UT HW10: #6

I did P=Po+rogh but it didn't work, I don't know what I'm doing wrong....and I also don't know what numbers I'm supposed to be plugging in: the oil or the water?

UT HW Extra Credit #39

I think this has to do with momentum, but I have no idea how to go about doing it

UTexas HW7 #17

I might know how to start it, but I am completely winging it. Can anybody help me?

UT HW7: #15

I got 14, and I thought this was an energy problem, so I did mgh=1/2mv^2, but it didn't work. What should I be doing?

uTexas HW7 #18

I got question 17, but I don't see how we're supposed to find the maximum compression without knowing the spring constant. Can anyone help me out?