Today my English teacher told us that we you can't lift a four-legged chair (of avg weight) if you only lift from the bottom of one leg. All the students tried and none of us could. What is the physical explanation of this? I'm guessing it has a lot to do with the moment of inertia of the chair increasing if you only grab the chair from an end at the bottom of one leg, but I'm pretty sure there's more to it than that- maybe something to do with torque? (Try to attempt this yourself to get what I mean- it's actually really cool).