Mishnah 7 in the third chapter of Tractate Bava Kamma deals with a person who causes damage not directly with his body, but with his force - through his actions and the energy he invests in them. The case discussed is a person chopping wood.
If a person is standing in the public domain and chopping wood in a public place, with people around him and one of them gets hurt - it is obvious that he is liable for the damage, since he acted with complete irresponsibility. However, one might have thought of two cases where he would be exempt:
The one chopping in a private domain: A person chopping wood on his private property, in a place where he is permitted to be and permitted to chop. One might have thought that if he did not intend to hurt anyone - he would not be liable for the injured party.
The injured party is in a private domain: The one chopping is standing in the public domain, but the injured party is located in a private place where people do not normally frequent - such as an isolated corner of a large farm, where no one happens to be, and a person arrived there and was hurt by indirect damage: wood chips that flew off, or the axe blade that detached and flew.
In both of these cases, the halachah is not so. The one chopping bears the responsibility to pay attention to what is happening around him, and "a person is always considered forewarned" - and therefore he will be liable for full damage.
The language of the Mishnah:
"Hamevake'a birshus hayachid vehizik birshus harabbim" - A person chopping wood in his private domain, on his own private property. While he is permitted to do so, the responsibility still lies upon him to ensure that no one gets hurt; therefore, if the wood or the axe head flew into the public domain and caused damage - he is liable.
"Birshus harabbim vehizik birshus hayachid" - He is chopping in a public place, and the injured party is located in an isolated, private area where no one is usually found. Even here, the responsibility to look is upon him, and therefore he is liable.
"Birshus hayachid vehizik birshus hayachid acher" - Even when both factors are combined together: a person is chopping wood on his private property, in a place where he is permitted to be, and the wood chips fly into another person's backyard who is generally never there - this makes no difference, and he is liable.
The foundation of these matters is the rule that "a person is always considered forewarned": a person must ensure that no one is hurt by what he is doing, the responsibility to guarantee this lies upon him, and if he caused damage - he is responsible to pay for any damage he caused.
In summary: In this Mishnah we learned that one who causes damage through his force - such as one chopping wood - is liable in all three cases: when he chopped in a private domain and caused damage in the public domain, when he chopped in the public domain and caused damage in a private domain, and when he chopped in a private domain and caused damage in another's private domain. It is not enough that he is in a place where he is permitted to be, or that the injured party is in a place where people do not normally frequent, since a person is always considered forewarned and it is his responsibility to pay attention to what is happening around him.