The SI unit for momentum is kg*(m/s)
<span>The eastern margin is a convergent boundary subduction zone under the South American Plate and the Andes Mountains, forming the Peru–Chile Trench. The southern side is a divergent boundary with the Antarctic Plate, the Chile Rise, where seafloor spreading permits magma to rise.</span>
Melting tin and then cooling it into a mold is an example of reversible physical changes.
<u>Explanation:</u>
When an object undergoes a change in size, state, or shape and not in their chemical compositions referred to as physical change. But chemical change occurs as a result of the change in substances composition. It also forms a new one by the combination/ breakage of one or more objects.
In the case of making gold cube into two pieces, there is no possibility of getting the original state again even the physical change happens. Match burning and relighting and sodium plus chlorine forming table salt show chemical change. But in tin melting and cooling it to form mold is the physical change i.e changes in state(liquid to solid) and are reversible too.
As simply put as I believe is possible, it's the immediate space-time co-oridinate in which the observer is not in motion. All measurements by the observer are in relation to that 'place'
