We have just purchased a Samsung galaxy tablet 10.1 and there are no directions for charging - so we put the adaptor together to plug into the wall and it does not come apart - why is it in two separate pieces and why can't we get it apart? Thank you
It's to make it cheaper to manufacture in bulk. The part with the actual transformer in is the same for every country, and the other half (with the plug itself) is different for each country. Making the complicated part global means they don't have to redesign the whole transformer for each country, and the manufacturer can benefit from increased economies of scale, reducing the price.
Most transformers for today's gadgets follow the same design. In the drawer in front of me I have examples from Apple, Sennheiser, and Asus, as well as Samsung, all in two parts.
Usually, it is possible to take the two pieces apart again, it just needs a bit of a wiggle and some practice. This makes it easier to use another country's plug if you're travelling, but apart from that there's no reason to. If you can add a photo of the particular kind of adaptor you have, I can probably add instructions for how to take it apart.