# Recent content by kkrizka

1. ### Gyroscopic Forces?

A normal spinning top will spin forever, at least in theory. However in reality there is friction, which will slow down the top over time. This will be the case with any contraption that you can come up with.
2. ### Minimum Energy Of A Beta Particle

Homework Statement When Ne (Z=10) decays to Na (Z=11), what is the maximum kinetic energy of the emitted electron? What is the minimum energy? What is the energy of the neutrino in each case? Ignore recoil of the daughter nucleus. Homework Equations E = mc^2 The Attempt at a Solution The...
3. ### Rubber bouncing balls

I think he is talking about that demonstration of momentum where you have several bouncing balls on top of each other, let them fall and then watch the top one bounce up very high. The question then is, is it possible with enough balls/starting height to have the top ball reach escape velocity...
4. ### Ignoring Rotation Of Earth

What do you mean they would "resist" an ideal scenario? I'm assuming that by ideal, you mean the scenario mentioned in my assumption (no rotation, uniform density...), but I'm not sure how a force could "resist" something. So I hope you could clarify that point. Well, that's what I though too...
5. ### Interference of waves from two sources.

Umm, try to draw the picture. You don't need to use Pythagoras.
6. ### Interference of waves from two sources.

4.47m from point A??? :confused: How?
7. ### Interference of waves from two sources.

You do not need the distance in this case, because the three points (two points sources and the location you are interested in) lie in a straight line. Since it is the difference in distance that you are interested in, for a straight line this is just the distance between them.
8. ### Interference of waves from two sources.

L should be the distance between the two point sources, so L=2.
9. ### Interference of waves from two sources.

Yes, that is exactly what it means. Since the distance is not a multiple of the wavelength, the crests do not line up with each other and neither do the troughs. Since it is not a multiple of wavelengths plus a half of a wavelength apart, the troughs do not line-up with the crests and so do not...
10. ### Linear momentum conservation - rocket

Assuming that v2 is the intial velocity of R block and v3 is the initial velocity of the C block, that statement is true. (Note: Initial means before the R block is shot off).
11. ### Differentials and area

Try to layout the tin can as a map. That is, if you cut the edges and and layed everything flat. How would it look like? Or lookup the equation for the surface area of a cylinder. No, deriative of something is how much one thing changes in respect to another.
12. ### Interference of waves from two sources.

What is L? The equations look right, I just want to see if you know what the variables mean. From your attempt, I think you got it confused with a very similar equation for resonance.
13. ### Archimedes Principle and bouyant force

That sounds about right. First you have the volume of pure iron (assuming the holes don't weigh anything ;) ) and then you have the actual volume. The difference should be the volume of non-iron stuff.
14. ### Ignoring Rotation Of Earth

Hi all, Some time ago I watched this http://www.youtube.com/watch?v=FAFUSbIs5KA". However in it I assumed that the Earth is not rotating and I would like to know what would happen if I did not make that assumption I do believe that if the Earth is rotating, it will affect the speed of...
15. ### Archimedes Principle and bouyant force

You were on the right track, but mass of the displaced water does not equal to the mass of the cavities. But the volume of the casting equals to the volume of the displaced water. Try to continue from there. I don't really understand what this question is asking exactly, so I'll leave...