what is acceleration?

[AntonioLao]

If acceleration is defined as force per unit mass (Newton's 2nd law of motion) then if there is a force, there is always an acceleration. If the force is zero whatever the value of the mass, the acceleration is always zero. There are four fundamentally accepted forces of nature. Is it possible to hypothesize that there should be four kinds of acceleration? One associated for each force. But not all particles felt the effect of all these forces except the force of gravity. So that there is only one fundamental acceleration derivable from the force of gravity.

[Guille]

The 4 fundamental forces have many things in common. For me, acceleration is one of them. Anyway, how would yo define those accelerations, a person can't think about ypes of acceleration, because, its too much.


another good question is if there were 4 different accelerations, would they have or need different formulas?

[AntonioLao]

another good question is if there were 4 different accelerations, would they have or need different formulas?

the definition of acceleration will always be the time rate of change of velocity. For circular motion, the absolute value of acceleration is constant but its direction is changing with respect to time. So that the scalar product of a general acceleration and its field metric (effective distance) of application is a Lorentz invariance.

[math]\vec{a}\cdot\vec{r}=c^2[/math]

[davidgow77]

The acceleration of an object is related only to objects constituting 3-dimensions (ie, those made up from protons and neutrons). Accelleration can be alternatively described as mass receiving energy via a force being applied to it. By this I mean that the energy transferred by the application of force to a 3-d object manifests itself as accelleration, and that the resulting inertia of motion (the constant motion of the object after it has been accelerated) should be measurable as an energy. Thus the energy of an object in motion should be E=mc^2 + (energy transferred by force).

This is sometimes referred to as an object taking on mass, but my reasoning here suggests that the mass of the object remains constant, with the energy transferred being manifested as motion. To explain this another way, say that an object is travelling an 10 m/s. To accelerate the object any further, a force would need to be applied that is over and above the energy required to accelerate the object from rest to 10m/s.

DG

[AntonioLao]

the concept of absolute acceleration is somehow subtly implied in Mach Principle (and Newton's experiment with the rotating bucket of water). Until now i'm still struggling to fully understand this principle but this principle was instrumental to Einstein's discovery of special relativity.