I've been struggling lately in translating the English concept of work. I am familiar with trabajar but I was told only to use that to describe a physical action. Like so:
The man is working. -- El hombre está trabajando.
But how do I translate these?
It is broken. (As in, "It doesn't work.") -- ???.
This is not working. (As in, "I am having problems.") -- ???
A working prototype. -- ???
What verb is appropriate to use, and why? Or are there idiomatic expressions that would fit?