just curious,
if i newbie and newly registered today,
an then i paid chopper member,
can i gain 30 activity in just 1 week ?

No, having a "Copper membership", doesn't give you the ability to gain activity more than what normal users can have in a bi-weekly period (14).
- Regardless of that, there's a way to gain 28 activities in a shorter time:
Can I get more than 14 activity in two week period?
No. However, you can technically get more than 14 activity in a fortnight if you sign up in between periods, but you can't get more than 14 activity in a fortnightly period. For instance, if the period starts on a Wednesday and you sign up on Tuesday you can get 14 points on Tuesday and another 14 on Wednesday providing the period has started. You will then have 28 activity points but won't be able to get any more until two weeks' time when the new period starts.