For Superman, one of the most famous stories is that, while a hundred thousand miles away, he hears lois lane cry as she falls off a building and is able to fly to the rescue and catch her in time. In that issue, the building is depicted as being 100 feet tall, meaning that she would hit the ground very quickly. For the sake of argument, let's say it will take about 3 seconds. That means that Superman, in order to catch Lois Lane just before she hits the ground, would have to be traveling at a speed of roughly 30,000 miles a second in order to catch her. This presents several problems in terms of physics:
The speed that Superman would be traveling at is 5.36 x 10^10 meters per second. That value is 2 orders of magnitude greater than the speed of light. Now, in the mythology of the superman Universe, when Superman is able to go faster than the speed of light, time goes in reverse (which presents a whole host of issues with physics in and of itself). However, since such a phenomenon was not depicted in this scenario, the only possible explanation is that Superman never achieved a speed greater than the speed of light, in which case he never would have caught Lois Lane
Ignoring the previously mentioned concern, there is the problem with force. For Superman to reach a distance 100,000 miles away in 3 seconds, he would need to acheive an acceleration equal to 1.78 x 10^10 meters per second squared (according to the equation v = v0 + at). Now, if we assume that superman has a relatively low mass, say 6.8 kilograms, that would still mean he would be traveling with a force equal to 1.2 x 10^11 newtons. That is nearly 300,000,000 times what the human body can withstand. And even if superman was somehow strong enough to survive that, there is absolutely no way that Lois Lane could.