Simply stopped

Step 1 is to try. It has been 5 days and no response from the OP. Sorry I get frustrated, but I used to teach Physics and constantly had students whine, "I tried for hours and can't see how to approach problem #1". I'd ask, "did you read the chapter? (all 3 pages). If so, did you notice problem #1 is exactly like example #1 with just a few numbers changed?".