Centripetal Force - Conservation of Mass and Energy

Centripetal Force

Any motion in a curved path represents accelerated motion, and requires a force directed toward the center of curvature of the path. This force is called the centripetal force which means "center seeking" force. The force has the magnitude.

Centripetal force keeps the planets in orbit. According to Newton's 1st law, all masses have inertia and would like to move at constant speed in a straight line. These objects have momentum. Earth wants to move straight but it is prevented from doing so due to the sun's gravity. The sun applies a centripetal force.

Conservation of Mass and Energy

Conservation of energy

The law of conservation of energy is an empirical law of physics. It states that the total amount of energy in an isolated system remains constant over time (is said to be conserved over time). A consequence of this law is that energy can neither be created nor destroyed: it can only be transformed from one state to another. The only thing that can happen to energy in a closed system is that it can change form: for instance chemical energy can become kinetic energy.

Albert Einstein's theory of relativity shows that energy and mass are the same thing, and that neither one appears without the other. Thus in closed systems, both mass and energy are conserved separately, just as was understood in pre-relativistic physics. The new feature of relativistic physics is that "matter" particles (such as those constituting atoms) could be converted to non-matter forms of energy, such as light; or kinetic and potential energy (example: heat). However, this conversion does not affect the total mass of systems, because the latter forms of non-matter energy still retain their mass through any such conversion.

Today, conservation of "energy"