Recent content by frankencrank

If we want to know the totality of the energy of an object/particle do we only have to look at the mass, since mass changes with speed, or do we have to also add the classical kinetic energy of the object to the changed mass energy? I think it is is former but it is not obvious to me right...

I have answered it. I did it earlier in this thread. It is not possible to know the energy losses assoicated with a turn without knowing the physical properties of the object that is providing the force to cause the turn. If one assumes a rigid object, then the losses are zero. Under almost all...

You can look at it however you want. I look at it as kinetic energy is being lost from the system in the form of heat due to the turning. I take that as the turn requiring energy as it would not be there except for the turn. Actually, except under special circumstances, even orbiting...

The example cited works for your challenge. Yes, the energy is lost in material stress and strain of the pole. But, it is the pole that is providing the force to do the turning. Therefore, energy is being lost from the system and so there is an energy cost to the turning. If the turning had not...

Grasping at straws, not at all. It depends upon what that rope is attached to. It it is attached to another equal particle then you are right. Then we have a spinning disk scenario. But, that is not the scenario we were examining. We were looking at turning a single mass. So, in this instance...

Actually, all materials stretch some when force is applied. This means work is being done even though the distance may be small in a kevlar rope compared to a rubber band. Physics problems usually assume no stretching to make solutions easier and help people to see concepts but in many...

Actually, I think I did get it wrong as I was thinking about this out on my bike ride. However, I think the general principle is correct. What I got wrong, I believe, is the particle in the cyclotron should have the fewest losses of those that I listed, not the most. The reason is the force is...

As I have been thinking about this overnight I believe I understand the issues now. I would like to get some confirmation from the experts here. The amount of loss in turning an object depends upon the amount of work involved in providing the necessary forces. Work equal to force x distance. In...

How about this way of looking at the problem. the energy required depends upon how the force is generated. Lets take the case where a massive object is swinging around a center pole unbalanced by an object on the other side. Depending upon the tensile strength of the pole there will be a...

If we don't know the speed of the exhaust can we calculate the expected energy requirement by looking at the deviation. What if we looked at a series of collisions between moving balls. In such a collision, momentum is conserved. In this series though in each collision one ball, when it hits...

This is how I see it. The same outside force applied to a single moving particle or object can result in only 3 outcomes. 1. It increases or decreases the speed without changing the direction of motion. This results in a change in both kinetic energy and momentum. 2. It increases or decreases...

It is not "fair" to change the problem to make the solution easy. You have now described a two particle system where momentum is conserved. I described that system in the original post. The original question/problem is one particle system. Is it possible to change the momentum of that particle...

Is it right to say that that "work" done on each individual particle spewed out by the rocket when summed is the "equivalent" of work done to change the direction of the spaceship? We certainly can know the energy of each particle and the sum of the energy spewed into space. The energy per unit...

Another way of looking at the problem would be to fire an infinite number of tiny bullets directed at 90º from the direction of motion. We would know the energy of each bullet and the reactive thrust of each bullet and could solve the problem, I guess, that way. I will let the experts here...

No, you misunderstand. The thrust of the rocket by definition would always be delivered at 90º to the direction of movement at the time so there would be no slowing of the spaceship. Such a force, if continued for a period of time, would eventually result in a 180º turn as it replicates a...