The magnetic field at any point is described in terms of the force that it exerts upon a moving charge at that point. The electrical and magnetic units are defined in terms of the ampere, which in turn is defined from the force of one current upon another. The association of electricity and magnetism is also shown by electromagnetic induction, in which a changing magnetic field sets up an electric field within a conductor and causes the charges to move in the conductor.

mechanics

Science of the action of forces on material bodies. It forms a central part of all physical science and engineering. Beginning with Newton's laws of motion in the 17th century, the theory has since been modified and expanded by the theories of quantum mechanics and relativity. Newton's theory of mechanics, known as classical mechanics, accurately represented the effects of forces under all conditions known in his time. It can be divided into statics, the study of equilibrium, and dynamics, the study of motion caused by forces. Though classical mechanics fails on the scale of atoms and molecules, it remains the framework for much of modern science and technology.

The word hotel derives from the French hôtel, which referred to a French version of a townhouse or any other building seeing frequent visitors, not a place offering accommodation (in contemporary usage, hôtel has the meaning of "hotel", and hôtel particulier is used for the old meaning). The French spelling was once also used in English, but is now rare. The circumflex replaces the 's' once preceding the 't' in the earlier hostel spelling, which over time received a new, but closely related meaning.