The discussion centers around the nature of kinetic energy as a scalar quantity, exploring the definitions and properties of energy in relation to velocity. Participants seek clarification on why kinetic energy is not considered a vector and request additional examples beyond kinetic energy.
Participants generally agree that energy is a scalar quantity, but there is some contention regarding the explanations and references provided. No consensus is reached on the clarity of the initial article referenced.
Some statements rely on definitions that may not be universally accepted, and the discussion includes varying interpretations of the relationship between velocity and energy.
This is not an appropriate reference. In order to know what you read we need to know which article. Please provide a reference.nineteen said:I read in an article
Orodruin said:Energy in general is a scalar quantity. It is how it is defined, whether kinetic or potential.This is not an appropriate reference. In order to know what you read we need to know which article. Please provide a reference.
The inner product of any two vectors is a scalar quantity. So in particular, the inner product of a vector with itself, i.e., the square of the vector, is a scalar quantity.
anorlunda said:Try to think of it in these common sense terms.
Momentum, which is proportional to velocity, is a vector quantity. When two cars collide, it makes all the difference in the world if they were traveling in the same direction or in opposite directions.
Energy is proportional to the square of velocity. It takes the same energy (fuel burned) to accelerate a car from a stop to cruising speed, or to travel 100 km, regardless of whether the car is heading north, south, east or west.