A common sight in zombie movies is the notion of barricading a set of double doors to keep out dozens, hundreds, or even thousands of zombies. This notion is quite ridiculous and even worse, some people think a single person can do it.
This has made me wonder, ignoring fatigue, how strong/big/heavy would a person need to be to hold back a dozen fit, well exercised humans? What about a hundred?
One person, using their full body weight with a strong stance, can push about 225N. This means that 10 people, evenly distributing their force, could push about 2250N (or 500 lbf). This number, while not massive, is still large enough to break down a door or move a car. The would also depend on how spread out the force is, if the people (or zombies) are layered behind each other, the strength of whatever they are pushing, and how the person holding the door is positioned. I would guess, if all people had equal strength, even 3 people could overpower someone trying to hold a door closed. The defender would have to have a very large mass, and a lot of friction against the ground. A couple hundred pound linebacker with spiked shoes could probably hold off 10 zombies pushing on a door.
Well if people are desperate, they draw out more of their strength. Also they don't have to hold off the zombies themselves .... they can just barricade the doors.
