A heat engine uses thermal energy flowing from a heat source that is 225 K to a cold sink that is 50 K. What is the approximate efficiency of the heat engine? 22% 45% 78% 123%.

Which levels of government establish and implement educational requirements for minors

Acertain radio station broadcasts radio waves that have a wavelength of 298cm what is its broadcast frequency?

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.