Conservation law, also called law of conservation, in physics, several principles that state that certain physical properties (i.e., measurable quantities) do not change in the course of time within an isolated physical system. In classical physics, laws of this type govern energy, momentum, angular momentum, mass, and electric charge.
On New Yearâs Eve, the Metrorail system will open at 7 a.m. with special extended service on all lines until 3 a.m. The additional three hours of service â consistent with past years â is a special exception to a moratorium on extended hours during the year-long SafeTrack maintenance program.
Shopping Hours: General Guide. City shops generally open from 9:00am to 5:00pm but some have hours of 10:00am till 6:00pm, Monday to Friday. On Friday, many shops in the CBD and suburban shopping centres remain open until 9:00pm.