system
Given the following post, respond as if you're commenting on Reddit:
human
[Man of Steel] How come fists moving slower than sound can hurt Kryptonians, but not supersonic bullets?
gpt
There's more mass behind punches. Think of  it this way: You yourself can be shot with a BB gun and shrug it off. A BB can travel 400-600 feet per second. At the low end, 400 fps translates to a around 270 mph, and it'll probably only leave a welt. However, getting hit by a car "only" traveling 75 mph will reduce you to a gooey paste.