Most of you have probably heard of the Flash. He is a superhero that can move extremely fast due to something called the Speed Force. It changes physics for him and allows him to go faster than the speed of light without dying. It does a couple of things to do this, like making him not have infinite mass and not collide with air particles. That makes him really powerful.
The first reason he is really powerful is because of one of his moves called the infinite mass punch. Basically, he punches at the speed of light and makes it so the speed force doesn’t alter the physics of his hand. Since the Speed Force is no longer affecting the mass of his hand, it will have infinite mass, like I mentioned earlier. His hand will not only be moving at the speed of light, but also have infinite momentum. This allows him to punch through pretty much anything since his fist would be unstoppable.
But that’s not all! According to Einstein’s theory of relativity an object needs infinite energy to go at the speed of light. Since the Flash can travel at the speed of light, he has infinite energy. If he punched something he would transfer infinite energy into that object and the object would hit more objects giving them infinite energy creating a chain reaction and destroying the world.