Mechanical energy nonconservative forces, like frictional forces, will be present, but often they are of negligible values and the mechanical energy's being constant can therefore be a useful approximation. In elastic collisions, the mechanical energy is conserved but in inelastic collisions, some mechanical energy is converted into heat. The equivalence between lost mechanical energy (dissipation) and an increase in temperature was discovered by James Prescott Joule. Many devices are used to convert mechanical energy to or from other forms of energy, e.g. an electric motor converts electrical energy to mechanical energy, an electric generator converts mechanical energy into electrical energy and a
Homosexuality: A Psychoanalytic Study of Male Homosexuals are consistent with those of Bieber's work. They maintain that Bell "et al."′s finding that "detached-hostile father" is relatively characteristic of 52% of the white homosexual men in their study and 37% of white heterosexual men is quite similar to what was reported by Bieber "et al". The philosopher Timothy F. Murphy described Bieber "et al."′s research methodology as flawed. William Spurlin suggested that "Homosexuality" informed stereotypes later promulgated by the media. Homosexuality: A Psychoanalytic Study of Male Homosexuals Homosexuality: A Psychoanalytic Study of Male Homosexuals is a 1962 book about the development of male homosexuality by the psychoanalyst Irving