grammar - When it is appropriate to use "-ing" in a dependent clause?

I tend to use sentences like these ones in my writings:

"Bob kicked the boy, injuring his left knee."

"Congress passed the brand new tariff act, increasing the prices of
imported goods."

What is the specific rule for using these types of of dependent clauses (..., "verbing")? I do not know when their usage is incorrect. I feel like I use them whenever it "feels right," but I do not know when it is actually grammatically correct to use them.

Also, does the "increasing" in the second sentence refer to "Congress" or the "act"? If it is the act, then do all cases of "-ing" in the start dependent clause refer to the noun right before it?