# Search results

1. ### Finite Blackholes?

This Black Holes FAQ appears to be accurate and will answer your basic questions: http://cosmology.berkeley.edu/Education/BHfaq.html#q5 There is a theory of black holes on a quantum scale that might be tested with the newest and biggest particle colliders. So they can be tiny. To me, the...
2. ### A point is stronger than a plane?

Rutherford's gold foil experiment exposes some of the logic applied on this thread. This is a short shockwave flash explaination of shooting alpha particles at gold foil: http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf Two postive charges cannot occupy the...
3. ### Gauss' Theorem for gravitational force

My recollection of solving these problems is to use symmetry in choosing coordinates: http://hyperphysics.phy-astr.gsu.edu/hbase/sphc.html where you have chosen x,y,z coordinates and gravity has a spherical distribution in the simple case.
4. ### Force Between Two Plates

The two problems are (A) finding a model for the force; and (B) confirming the model. If it is possible to measure a change in pressure or deflection of the plates you have a means to evaluate your model. I am not sure how difficult a measurement would be ...
5. ### The equation of a roller coaster loop

Also I was thinking some drivers might exploit a similar principle in the choice of racing lines. Very interesting topic.
6. ### Damping Ratio

Please be more specific. I think the only damping constant is r2 and the time constant is either a simple ratio or product of k2 and r2.
7. ### Coupled damped harmonic oscillator

Another question, doesn't the flow of air past an object cause oscillations that could account for your results? For example, an open jacket on a motorcycle rider flaps up and down on each side at a natural frequency due to alternations in shedding a vortex. The back end of a big rig has a side...
8. ### Coupled damped harmonic oscillator

If time and budget permit, I would first create a rig to measure the coupling or lack thereof of torque with compression or elongation of a single spring, using a rig that permits testing of different joint methods to the deck. Next consider whether an imbalance in the linear spring...
9. ### Trying to understand this concept

Orbital mechanics are complicated but the basic principle is centripital force. The moon has tangential velocity so it is constantly falling toward the earth without getting much closer or farther away (it is changing its orbit over very long periods of time, I think, getting farther out)...
10. ### Vector cross products and dot

Cross Product Wiki: http://en.wikipedia.org/wiki/Cross_product Dot Product Wiki: http://en.wikipedia.org/wiki/Dot_product
11. ### The nature energy

DaleSpam, I appreciate the extra effort. I must investigate the nature of invariant reference frames to improve my understanding. It is still my understanding that the Conservation Laws only allow us to measure and specify that the change in energy during an interaction, measured in both...
12. ### The nature energy

DaleSpam, I appreciate your concrete example and effort to address my question. Look at it again. Doesn't your example demonstrate my original closing comment where an observer applies a law of physics, describes standard units of measure, and then considers the net change in energy during...
13. ### The nature energy

DaleSpam, "A number without a unit is meaningless," my old professor used to say. When I measure zero of some quantity, I do so with respect to a positive definition of that quantity, and I assume something positive is absent in the problem. An example is NASA failure due to confusing MKS...
14. ### The nature energy

Yes, I confused the appropriate terms used for conventional number theory. Still, calling zero or negative numbers "real" does not imply anything other than a conventional name. I think my points are valid just the same.
15. ### The nature energy

Zero is a memory process. If I say "there are zero elephants in the room," you must first imagine one elephant to understand the quantity "zero elephants." Elephants exist but zero elephants exists as an imaginary number, not as zero elephants! Can you measure zero without a positive definition...
16. ### The nature energy

This concept of absolute versus relative "energy" has me confused. I am not a theoretical physicist, but it seems to me, zero is an imaginary number, and there is no way to measure "zero" anything. Therefore when we assign a number value to a measured quantity, we always assign some state...
17. ### The effect of battery in parallel

There are some great animations showing potential and flow analogy at the bottom of this page: http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/DC-Current/WaterFlowAnalog.html [Broken]
18. ### Coupled damped harmonic oscillator

My background is EE but I've been doing some basic simulator work. It looks like there are four helical springs above and four below the deck. First question, does a helical spring inject a torque on when it compresses? My intuition says it does unless there is decoupling provided at the...
19. ### The nature energy

Is this based on the arbitrary choice of sign convention for work done on or by a system? If not, could you provide an example of this type of observation? Do you regard E = mc2 as indicating a relative or absolute amount of energy? My intuition says it is relative if only due to the fact...
20. ### The nature energy

Pilots and race car drivers with greater skill also have a greater sense of energy. Bringing this up to the conscious level is powerful, yet birds of prey also use energy much like a pilot, and glider pilots are now learning much about effective energy strategies from birds. The shape and...
21. ### Coupled damped harmonic oscillator

What type of spring configuration is responsible for the motion? It seems to me you either need a model based on the geometry and properties of the actual device, or you need a statistical/numerical model that can extract a coupling factor from measured data.
22. ### The effect of battery in parallel

If you're actually building these circuits to learn I suggest buying an inexpensive digital multimeter. Avoid using high voltage batteries and be sure not to create a short circuit across the batteries! I built a device that works on two 1.2V recharagable cells in series, but inside a case...
23. ### The effect of battery in parallel

The sketch shows the voltage at three nodes X, Y, and Z. The voltage on a node is uniform since lines represent perfect conductors in a circuit sketch. Ohm's Law applies on the lit bulb and the unlit bulb: V = IR where V is the voltage difference across the two terminals and resistance...
24. ### The effect of battery in parallel

Do you recognize the difference between a closed circuit and open circuit?
25. ### The nature energy

Conservation of Energy in Thermodynamics postulates the equivalence of work, heat, and energy. The measurement of work is something equivalent to raising a weight against the standard gravity. This means measuring force (weight) times displacement (height change) in a fixed Earth reference...