A4.0-kg mass, initially at rest on a horizontal frictionless surface, is struck by a 2.0-kg mass moving along the x axis with a speed of 8.0 m/s. after the collision, the 2.0-kg mass has a speed of 4.0 m/s at an angle of 37° from the positive x axis. what is the speed of the 4.0-kg mass after the collision?

here we will use momentum conservation along X and Y direction.

for X direction we will have

Now in Y direction we will apply momentum conservation

Now net speed of the object is given by

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.