The university is coming to the final exam, and we have to take five subjects seven days a week. Naturally, everyone will study hard. But some people are good at learning technology and have learned everything they usually need. Just look at the examples properly before the exam. There is basically no pressure to review in this way. I go to bed early at night, but some people sharpen their knives at the last minute. They haven't studied anything before, and then suddenly they have to work hard to improve their grades in order to pass this course. So time is tight, they will stay up late to review.
When encountering such conflicts in daily life, we should learn to communicate actively. Because most contradictions can be solved through communication, the other party can take some measures to reduce the influence of lighting on you, such as turning down the lighting to ensure that he can see his homework clearly, such as buying a bedspread, which will naturally have less influence on others. The other party can reduce the influence on the roommate by adjusting the schedule, reducing the lighting, or installing foreign objects. This is not an irreconcilable contradiction, but if you don't say it, the other party may think that you are indifferent to the lights.
There has always been such a gap between people's life and rest, whether it is the time of sleeping or the requirements for sleeping environment. Some people think it doesn't matter if there is a little sound around them, and a little light doesn't affect their sleep, but some people are harsh on the sleeping environment, and they can't sleep with a little sound and light, so they should learn to communicate with their roommates actively, because everyone has no experience before and naturally need to understand each other.
If the ship just avoids the dangerous area, the ship will travel in PQ direction at speed V.
As shown in the figure, v 1 is the water velocity,
Then the speed