20. A motorboat heads due east at 11 m/s relative to the water across a river that
flows due north at 5.0 m/s. What is the velocity of the motorboat with respect to
the shore?

i dont think you are wrong for wanting to get even with someone who did you wrong.

(i'm an eye for an eye kind of person) but if this person hurt you in a sexual way, i dont suggest doing anything to him. he should be taken to the proper authorities, you could go to jail depending on what you do. if it was something small like your sibling took your spot on the couch, than yea, i would get even with him by taking one of his favorite snacks lol. but i dont suggest you doing anything illegal.

i need with 1.3.2 investigate cycling o2 and co2 apex

we need to see it

3. dark matter

empty space could also be a simple vacuum