Men in Black tells the story about a secret society of men who sacrifice everything in order to keep the general public in the dark about the presence of aliens who live on Earth. The two primary characters, the veteran Agent K and his rookie partner, Agent J, battle to prevent the destruction of the planet Earth by an evil bug.
The first example of horrible physics occurs in the first few minutes of the movie. As Agent K converses with an alien trying to sneak over the Mexican border to the United States, a curious border agent sees the scene. When the alien charges at the human, intent on hurting the human, Agent K is forced to kill the dangerous alien. Teal slime is spattered over an area of 20 yards. What classifies this as bad physics lies in the gun that is used on the alien. The force that the gun exerts is very strong because of the residue from the alien that is flung out in a wide area. Good physics requires that the gun would have jerked back when it was shot. The force released would have made Agent K stumble back at least a few inches, if not a foot. However, Agent K was unaffected; it was as if he had shot something that had as little power as a water gun. This violates Newton’s third law: for every action there is an equal and opposite reaction.
Men in Black was a good movie that, just as any other Hollywood production, had sacrificed the truth of physics in order of the movie to be entertaining and short. While the movie did have a few scenes that did violate some of the major laws of physics and science, I believe that it made an attempt to follow the rules of good physics. This is why I decided to give the rating of PGP-13 to the movie Men in Black.