In mechanics, a force is that which causes a change in velocity or, if you prefer, that which causes an acceleration. When more than one force acts on an object it is the net force that is important. Since force is a vector quantity, use geometry instead of arithmetic when combining forces.
Quick Answer. A crawling sensation felt on the skin may be caused by a condition called morgellons, according to WebMD. Common symptoms of morgellons include feeling like bugs are crawling on the skin, burning, itching and stinging sensations. In some cases skin sores may appear as well.
People who are addicted to certain drugs such as cocaine have the feeling of bugs crawling on the skin. In contrast to the above, feeling of crawling may be really associated due to bugs. Bed bugs, Sarcoptes scabi which causes skin condition scabies is associated with crawling feeling. However, the sensation is accompanied with itching, rash and bumps.