If a woman was trained well enough in fighting could she have the strength to flip a guy onto his back? You see it in movies and tv but could it happen in real life?

Yes. It's all about leverage and the basic principles of physics.

Yes a woman can flip/throw a guy, sometimes with relative ease. Most well done throws are just a matter of balance and leverage. The center of gravity is in the hips, and when you do a shoulder throw for example, your hips go under theirs, lowering your center of gravity and creating leverage. You then pull them forward whilst knocking them off balance and your lower hips act as a sort of fulcrum heaving them over. It's basically the coolest application of physics for people who don't like math.

Now I will say that in a sparring match or something like that it will probably be harder for a woman to get a good throw in, but that's usually because of distance and striking range. If you can keep someone on the outside with good range, then they won't have the opportunity to throw you. Women usually have shorter reach, so though I'd say that they could easily throw a guy, it might be a bit harder then someone of similar size and build, but when you're highly skilled it's small inconvenience.

If you say flip you mean throw the answer is yes. It not strength that allow her to throw a male. It is in using good technique. It happens all of the time. Some women that aren't trained can do this too.

It can if you use the right technique, even as a guy, I'm able to flip other guys who are like over 100 pounds more than i am, so a girl who is lets say 100 pounds if trained correctly can take someone who is over 180 pounds w/o a problem.

Training is for that. At least after the training about 3-4 years, it can be done easily. I'm sure. No matter about the gender. I have seen it many many times. A skiny karate black belt girl could give a bloody nose to a well built 6 feet taller muscular guy. Everyone has weak places like nose, groin, chin, eyes, middle of the chest...............

I dont think its about strength as much as it is technique (i think thats the word). All about the path of least resistance. I would spar with my cousin sometimes whos bigger than me. One time i realized the back of his foot was up so i acted like i was going to the opposite side and he lifted it up more and i was able to sweep my leg under him and he went down really fast haha

Duh.

Their gender has nothing to do with anything. I've seen 120 lb women flip 185 lb men like nothing in training.

Strength helps, but a-lot of the techniques used in Judo etc, do not fully rely on strength, but simply their technique.

It has less to do with "strength" (though it is important) and more to do with leverage and timing.