CIE AS Physics -MCQ help!

[nox_fjmoony]

So I was doing physics mcq's the other day and well I guess I've got a lot of problems here.
I was solving the may/june-02 and oct/nov-02 paper-1 question papers and these are the questions I had trouble with.

May/june-02
Question numbers: 5,6,14,21,31.

Oct/nov-02
Question numbers: 6,7,8,9,10,11,12,14,15,17,18,21,22,24,29,31,32,35,36.

I know the answers thanks to the mark scheme, but I don't understand the idea/reasoning/logic behind them, if someone would kindly explain them to me, I'd really appreciate it. I need help here.

Thanks
^ ^

[astarmathsandphysics]

Will have to answer it tomorrow

[astarmathsandphysics]

Lot of questions. Post them a few at a time else I feel intimidated

[nox_fjmoony]

Oh okay then. Never thought it might seem intimidating to you Astar.
Well then here goes:

Oct/nov-02
Question numbers: 6,7,8,9,10,11,12,14.
these for now?
I've got a test tomorrow see, I need to understand them.
Ah, wish our school would teach properly for a change
:\

[astarmathsandphysics]

Sodit I thought they were all long answer qs. I will try now. I have to go out now though so I will have to do it when I come back in about 5 hours.

[astarmathsandphysics]

6) A and B have large no systematic errors and D has a large randome error so ANS=C
7)t waves into 5 squares=50ms so 1 wave into 7ms s0f=1/7ms=1/(7*10^-3)=140hz roughly
8)only A - the horizontal acceleration is always zero.
9)use s=ut+1/2 at^2 over the whole distance so u=0 and t=t_2 then h=1/2at_2 ^2 so a=2h/t_ ^2
10)As the ball speeds up air resistance will increase so acceleration ( the gradient) will decrease A or D -frankly not much difference.
11)A for elastic collision approach speed =separation speed
12) conservation of momentum
60m-30m=2mv s0 v=15 A
14)moments about pivot 20*60-100*10=50d so d=200/50=4 so at 40+4=44cm point

[astarmathsandphysics]

If you want any more questions answered I am back in about 5 hours.

[nox_fjmoony]

OwO
Th-Thankyou!!!

These are all for now
Thanks for helping.