i dont really understand this stuff cuz our professor sucks ass and doesnt explain anything.
if someone can explain to me how to do these or give me the answers to these, will pay FG should be getting around 700 today thank you!

for number 2
d=vt , distance= velocity*time
average velocity , v=d/t

The way you calculate uncertainty for multiplication and division is the same
For your problem

uncertainty of velocity = (velocity) * sqrt [ (uncertainty of distance / distance)^2 + (uncertainty of time / time)^2 ]


have a read
http://lectureonline.cl.msu.edu/~mmp/labs/error/e2.htm