I need someone to answer this physics question for me please. I have no education in physics, save basic high school sciences, so I must apologize for this question if it sounds stupid to you. My brother and I have been quarrelling over this all day. He and I were playing the video game "Mega Man X" for the old super nintendo the other day. I was at a part in the game where the protagonist hops onto a mine cart and goes flying thorough a mine shaft. The protagonist is equiped with a projectile weapon on his arm and as he fires it while riding the mine cart, the projectiles travel very slowly away from him whereas the projectiles travel much faster away from him while he's standing stationary. I've established that the projectiles have a set speed whether they are being fired from a stationary postion or from the speeding mine cart. My little brother said that that would happen in our universe and him being an idiot I wasn't quick to believe him. Suppose I were driving down a straight highway with no one around for hundreds of miles (thus making this experiment safe) and I had a handgun in my left hand. Let's also suppose that I could shoot the gun in an exact straight line realtive to the car, but next to it. I don't know exactly how fast a bullet will travel but let's also suppose that the car was going almost as fast as the bullet, let's say ten miles an hour slower than the bullet. Here's my question; will the bullet travel away from the car at ten miles an hour or will the bullet travel away from the car at the speed of the vehicle plus how fast the bullet would travel if fired stationary? Or is there another possibility I have not taken into account? Do you understand the question? It's my fault if you don't, like I said I have next to no science education, except for basic high school classes and an infatuation with physics books. I also haven't put too much thought into the wind resistence and gravity....I wasn't exactly sure how to factor it in there. Again I apologize if this is a stupid question.