Please explain what this means.. ?

[PitotTube]

Hello flight instructors,

I would be very happy if someone could help and do some explaining.

1. what a porpoised landing is?
2. what a balked landing is?
3. where can I find the definition for aerobatic flight?

4. why I cannot find an "arm" for the fuel in a C150/C152 POH, but have to calculate it from an example in the book? some say it is 40.0 some say it is 42.2?

5. if a plane is porpoising, what is it doing then??

thanks