تسجيل الدخول

تسجيل

General Law

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-287

2025-11-25

568

 We have seen that both friction and collision give rise to heat. The work required to overcome the friction in a machine is, from the mechanical standpoint, lost work; in reality it is work transformed into heat. The relation between mechanical work and heat was investigated by Joule, who established the following principle: The disappearance of a certain amount of mechanical energy produces an equivalent amount of heat. The converse of this law is equally true: The disappearance of a certain amount of heat produces an equivalent amount of mechanical energy.