Normal (geometry) Normal (geometry) In geometry, a normal is an object such as a line or vector that is perpendicular to a given object. For example, in two dimensions, the normal line to a curve at a given point is the line perpendicular to the tangent line to the curve at the point. In three dimensions, a surface normal, or simply normal, to a surface at a point "P" is a vector that is perpendicular to the tangent plane to that surface at "P". The word "normal" is also used as an adjective: a line normal to a plane, the normal component
Does Anybody Really Know What Time It Is? Does Anybody Really Know What Time It Is? "Does Anybody Really Know What Time It Is?" is a song by the rock band Chicago. It was included on their 1969 debut album "Chicago Transit Authority" and released as a single in 1970. The song was written and sung by Robert Lamm. The song was not released as a single until two tracks from the band's second album, "Make Me Smile" and "25 or 6 to 4", had become hits. It became the band's third straight Top 10 single, peaking at in the U.S. and No. 2 in Canada. Because the