Mechanical Engineering - Engineering Mechanics - Discussion

According to the law of conservation of energy, the energy neither be created nor be destroyed.

It is the law of conservation of momentum.

If it is vacuum then external force is required to stop.

If not at some point the body goes to the rest position.

I think option (a) is correct as -> Unless force external from the system is applied the system will continue to maintain its condition of constant motion or of stationary position.

Conservation of ENERGY.

It's true that motion is a change in displacement, but that doesn't need the continuous addition of energy to maintain as the conditions are always IDEAL in such questions.

Moreover, it's changed in motion which points toward change in energy not a change of position (Displacement). So motion in any direction is possible for a system that has a constant level of energy. (Imagine a ball in space which not in the influence of gravity from a body > if you give it a push it will start to travel with a constant velocity, NOW for this ball the total momentum of the system of masses (ball itself) in any direction remains constant unless acted upon by an external force in that direction. MEANING unless a force (or a force field) interferes with this system (WHICH (Force or force field) will be labelled EXTERNAL) the ball will go on its way beyond infinity (Literally).

According to the law of conservation, all momentum of the system will remain constant in any direction without acting any force in that direction. It will change when any force will act in that direction.

According to conservation law of energy, energy neither created nor destroyed, it changes its form from one type of energy to another type of energy.

The law of conservation of energy states that in a closed system the total amount of energy is conserved and does not change. This means that energy may change from one form to another, but that the total amount of energy in the closed system remains constant.

Principle of conservation of energy states that energy can neither be created nor be destroyed but can changes into another form.

And remaining statement shows about the law of linear momentum.

The law of conservation of energy, first formulated in the nineteenth century, is a law of physics. It states that the total amount of energy in an isolated system remains constant over time. The total energy is said to be conserved over time. For an isolated system, this law means that energy can change its location within the system, and that it can change form within the system, for instance chemical energy can become kinetic energy, but that energy can be neither created nor destroyed.

From: http://en.wikipedia.org/wiki/Conservation_of_energy

Principle of conservation of energy states that energy can neither be created nor be destroyed.