You need a lot of pressure to blow out the sprinkles. I believe its about more than 100 kph of pressure that is needed. The water is then blown from the hose and then it collects and builds into pressure to give out the water and thus, the water comes out.
Your question can't really be answered without more detail, there are too many variables and unknowns. For example - size of the system, age of the pipes, pipe material, etc.
That depends upon several factors, mainly the sprinkler's composition and structure (how it's built and what of) and the pressure of the atmosphere. In short, there is not enough information to answer this problem properly.
