Is it valid to speak of energy having an acceleration? Or a force having a velocity?

Question

Or are such concepts irrelevant to systems?

Answer 1

Maybe, for the energy question. Energy is a scalar. Acceleration is a vector. That is, energy has no inherent direction; so in general, we don't give it direction with acceleration or, for that matter, velocity or distance.

However, in tensors (a form of vectors math), we often attribute the flow of energy (dQ/dt) along the coordinates of a system. That is, we can map out how far (a distance) heat spreads throughout a system when starting at some given point in the system.

For example, the spread of heat throughout a solid body can be described as a flow of heat along the x,y,z dimensions of that body over time. In which case, the flow of heat has direction and presumably a distance of the spreading. And where there is direction and distance, we can derive an acceleration because d(dS)/dt^2 = a; where S is the distance vector which we differentiate twice with respect to time to get acceleration.

Maybe, also, for the force question. If we start with p = mv; which is the momentum of a mass m going velocity v, we can find force dp/dt = m dv/dt = ma; where dp/dt simply means a change in momentum over some time t.

So, it's a bit of a stretch, but we could say we started with a velocity to get the force. As f = ma and acceleration a is a vector, force is also a vector because a scalar (mass) times a vector (acceleration) yields another vector. Thus, force has direction as well as magnitude.

Not sure what "concepts" you are referring to. But direction is very important in systems. Direction is a major factor in all vectors. Vectors are made up of magnitude (like 60 mph) and direction (like due east). Distance, velocity, and acceleration can all be written as vectors; and these are all important concepts in systems.

Answer 2

Hmmm, Light is considered "energy" and it accelerates as it enters a black hole. Thats one thing.

There's a class called "System Dynamics" that uses the concept of Force as a flow of energy. For example, if I applied some force to a bolt connected to a wall, the force is seen to "travel" through the bolt to the wall in some manner similar to that of an electrical circuit (it takes the path of least resistance). In that manner, it can be considered to have a flow, or in other words, velocity. Fairly abstract but isn't everything in Physics abstract?

Answer 3

No. It's like speaking of 'mass' as having an 'aroma' or 'texture' as having a 'taste'.

But the concepts of energy used to -cause- an acceleration or force required to -cause- a change in velocity is valid.

Doug

Answer 4

I dunno