Engine Engine An engine or motor is a machine designed to convert one form of energy into mechanical energy. Heat engines burn a fuel to create heat which is then used to do work. Internal combustion engines are heat engines that burn fuel in a combustion chamber to extract work from the pressure of expanding gases. Electric motors convert electrical energy into mechanical motion; pneumatic motors use compressed air; and clockwork motors in wind-up toys use elastic energy. In biological systems, molecular motors, like myosins in muscles, use chemical energy to create forces and eventually motion. The word "engine" derives from
Dunlop Pneumatic Tyre Co Ltd v New Garage & Motor Co Ltd damages and not as a penalty’. The judge held the £5 sum was liquidated damages and enforceable. The Court of Appeal held the clause was a penalty and Dunlop could only get nominal damages. Dunlop appealed. The House of Lords held the clause was not a penalty, and merely a genuine preestimate of Dunlop’s potential loss, and so Dunlop could enforce the agreement. Lord Dunedin set out the following principles. Dunlop Pneumatic Tyre Co Ltd v New Garage & Motor Co Ltd It should not be confused with "Dunlop Pneumatic Tyre Co Ltd v Selfridge & Co Ltd", which held