Please remove the ridiculous 20 minute wait time for each additional question. I often have more than one question and do not see any reason to waste time. You are disrespecting the members of this forum with this unnecessary restriction. And this Ubuntu Meta is even worse a 40 minute restriction is also unacceptable.
If you earn 125 reputation the limit will be removed. The reason for this limit is to reduce spam questions, there is no chance it will be removed permanently. It is not disrespecting anyone, in fact it is improving the quality of the content on the site. If you really want to take this further you need to post on meta.stackexchange.com but it won't go down well.
Here is some information on how you can earn that reputation: How do I quickly gain reputation?
Until such time as you gain 125 reputation from the site (and therefore have your New User Limits removed here on Ask Ubuntu) you cannot post more than 1 question every 40 minutes on the site and its meta site (and this will apply anywhere across the StackExchange network where you do not have the requisite 125 rep on those specific sites). This is inbuilt rate limiting that has been around here for an eternity and is hardcoded into the StackExchange network and its sites.
The rationale behind the various rate limitations you are going to encounter until you get enough rep are all detailed in The Complete Rate-Limiting Guide on Meta.SE.
The specific part you're going to want to focus on is this:
Users with < 125 rep on the current site, 40 minutes since their last question anywhere on the network (This applies to the user's IP address, not their account. If the user shares that IP with other users, they can be limited by the other user asking a question anywhere on the network.)
- Other per-site limits may apply; e.g. on Stack Overflow, new users can only ask once every 90 minutes
- While the limit is waived for users with 125+ reputation on a given site, questions posted on sites where one has 125+ reputation still count toward the rate limit for sites where one doesn't. For instance, if you ask a question on a site where you have 150 rep, you can't ask another question on a site where you have only 100 rep for the next 40 minutes; however, you can ask them in reverse order immediately (first on the 100-rep site, then on the 150-rep site).
And keep in mind these restrictions specifically are network-wide so they apply on Ask Ubuntu, Superuser, Unix & Linux, Meta sites for each of these sites, etc. globally as defined.
Changes to this need to be proposed up at Meta.SE, as they affect all sites on the network, however I'm going to assume that you're going to run into a lot of flak with these 'requests' and proposals.