Try using another iOS 5.1.1 compatible third party web browser.
Some other older web browser can still access current Internet content.
The ones I can recommend is try downloading the current iCab Mobile web browser or Perfect Web Browser.
Try to download the latest app from the iOS App Store and if the developer has left an older, compatible version on Apple's app servers, then you will receive a small window pop-up prompt that states that there is an older version of the app that is compatible with your device. Would you like to download this version now.
Tap the OK button just below the prompt.
BTW,
An original 2010 iPad will be by, April this year, a 7 year old device!
Mobile devices don't stay supported forever, but I will admit, I feel Apple ended official support for the original iPad waaay too early (one year in) and made the original iPad 1 really an "early adopter" device/tablet.
So, in a very real way, the iPad 1 was a victim of the "planned obsolescence" theory.
New iPad models will be supported for, at least, 4-5 years by Apple and still be plenty useful for 2-3 years after support ends.
While I have an large iPad Pro, my wife and I still use an iPad 2 and 3 and I have an original 2010 iPad 1, that still has plenty of operational apps that I still use on my more current devices, that I keep charged up and still use from time to time.
Good Luck to You!