Ask a physicist anything. (6)

[Wiccan_Child]

-- I'm not allowed to bounce a basketball in the house.

Then do it outside, next to a large building where you can gauge the distance (perhaps in how many bricks or stories the ball flies up). Chalnoth is right in that the tennis ball will fly up very far, farther than you might think.

 

[Ba'alServer]

Correction - this is why I can't have nice things.

You are quite correct, Chalnoth. My apologies. All these years of my delving into religion have apparently rusted my neglected understanding of basic physics.

I used an online calculator to be sure that my algebra wouldn't sway my conclusions and found -

With 10 m/s initial upward velocity, peak is at time (t) = 1.02 seconds,
vertical displacement (Δy) = 5.10 meters

With 20 m/s initial upward velocity, peak is at time (t) = 2.04 seconds,
vertical displacement (Δy) = 20.4 meters

I'm glad there a people as patient and pragmatic as you working on things like the awesome Plank satellite. Nice results, by the way!

AV1611VET, this is why going by initial assumptions that may seem right isn't anywhere near as reliable as actually testing them out.

 

[Steffenfield]

Favourite: particle physics
Least favourite: electromagnetism and electronics. Those blasted resistors!


This is what would happen:

Jem Melts Rock Using Sunshine - Bang Goes The Theory - Series 3, Episode 5 Preview - BBC One - YouTube

Wow!

That was awesome!

So to get that level of concentrated energy from the sun, do you need one giant lens of unhappiness or could it also be possible by chaining a bunch of smaller ones together like I posted in my previous question?

Cheers WC!

 

[Chalnoth]

Wow!

That was awesome!

So to get that level of concentrated energy from the sun, do you need one giant lens of unhappiness or could it also be possible by chaining a bunch of smaller ones together like I posted in my previous question?

Cheers WC!

Well, you basically need two things:
1. A large collecting area.
2. A very accurate focus.

Whether you do this with one lens or many is largely irrelevant, though I strongly suspect that it is harder to do with many lenses than it is to do with just one.

 

[mzungu]

Mirrors are much more effective!

 

[Steffenfield]

How so?

Could you explain?

 

[Steffenfield]

Also, would someone care to provide me with the blueprints on how to build such a thing directly over my landlord's house?

 

[mzungu]

How so?

Could you explain?

Mirrors have lower losses.

Here is a good link to read: Encyclopedia of Laser Physics and Technology - focal length, dioptric power, curved mirror, lens equation, microscope, photographic objective, focus, beam radius

 

[GrowingSmaller]

I have just bouth a basic scientific calculator. What are the "stat" and "verif" modes for? Its a Casio fx-83GT PLUS btw. Any old links will do. I would like to learn how to use the thing.

 

[Wiccan_Child]

I have just bouth a basic scientific calculator. What are the "stat" and "verif" modes for? Its a Casio fx-83GT PLUS btw. Any old links will do. I would like to learn how to use the thing.

They're probably modes for entering data. "Stat" may be a way to enter data by telling the calculator that, instead of doing sums, numbers entered will be stored for later use. Then, you can tell the calculator to bring up the mean (or mode, or S.D., or w/e) of the stored data.

This is all off the top of my head. My own calculator is a graphical one, so when I'm entering data into a table I can visually see the table itself.

The manual for the Casio fx-83GT PLUS can be found here.

 

[chris4243]

Mirrors have lower losses.

Here is a good link to read: Encyclopedia of Laser Physics and Technology - focal length, dioptric power, curved mirror, lens equation, microscope, photographic objective, focus, beam radius

And here I was thinking, wait aren't mirrors at best only 95% reflective and so have the potential to absorb enough light to melt themselves if used at high intensity light? I didn't know they had these fancy new mirrors which act by constructive interference of Fresnel refractions from a hundred sub-wavelength coatings. 99.999% reflectivity, not bad .

 

[Steffenfield]

Could God really have made the Earth flat?

If so, how thick would the planet be so that we didn't fly away because of the low gravity?

Naturally, this is one of my less weirder questions.

 

[Chalnoth]

Could God really have made the Earth flat?

I don't believe any material could possibly support its own weight and still be large enough for its gravity to be noticeable.

If so, how thick would the planet be so that we didn't fly away because of the low gravity?

Well, if you wanted as much gravity as the Earth has now, and we imagine that it had the same density as the Earth, it would have to be a little over 4000km, or about 2500 miles thick.

 

[Wiccan_Child]

Could God really have made the Earth flat?

Depends on how much interference he has with the world. If he made the universe with the same physical laws, but intervenes to keep the Earth from breaking like a soggy biscuit, then sure.

 

[mzungu]

Could God really have made the Earth flat?

If so, how thick would the planet be so that we didn't fly away because of the low gravity?

Naturally, this is one of my less weirder questions.

Let us assume for arguments sake that God did make the Earth flat; This could easily be verified just by moving towards the horizon till you meet with the edge. But like you were told by another poster; gravity cannot allow for a flat earth at Earth mass and densities.

 

[Steffenfield]

Would it be possible to build an intensely concentrated PSI air bomb of unhappiness?

No chemicals. No toxins. Very low manufacturing and costs.

In today's new age of compassion, this just seems like it would be the more politically correct and nicer way of killing people.

So how close would this be theoretically possible on a large scale?

Cheers my fellow physics genuses (sp?)!

 

[pgp_protector]

Would it be possible to build an intensely concentrated PSI air bomb of unhappiness?

No chemicals. No toxins. Very low manufacturing and costs.

In today's new age of compassion, this just seems like it would be the more politically correct and nicer way of killing people.

So how close would this be theoretically possible on a large scale?

Cheers my fellow physics genuses (sp?)!

No, you can't build anything without using chemicals in some form.

 

[Steffenfield]

I really meant no nitro, C4, uranium, gun powder, etc. when I said no chemicals.

Touche on beating me with philosophy PGP.

 

[pgp_protector]

I really meant no nitro, C4, uranium, gun powder, etc. when I said no chemicals.

Touche on beating me with philosophy PGP.

I almost always chuckle to myself whenever I see anything advertised as "Chemical Free"
(Or every time I see a building stating all chemicals need to be registered, I so want to take em up on it (if I wasn't rushing ))

 

[Chalnoth]

Would it be possible to build an intensely concentrated PSI air bomb of unhappiness?

No chemicals. No toxins. Very low manufacturing and costs.

Not without chemicals, no. It would basically have to be some sort of mood-altering drug that depresses people. There is no way to have any significant, accurate influence on peoples' minds without some sort of physical contact, either through some sort of chemical or direct manipulation of the brain (pressure on certain areas of the brain can do all sorts of things, though that generally requires cutting open the skull...).