Physics - December 2007

2007-12-31 07:43:35 · 5 answers · asked by Anonymous

I know electrons and protons have opposite charges, but why did they decide the electron is negative and the proton is positive? What the the positive and negative words mean exactly? Why can't the electrons be positive and the protons be negative?

Understand my confusion?

2007-12-31 07:10:17 · 5 answers · asked by Anonymous

2007-12-31 06:50:38 · 4 answers · asked by robzr6 1

2007-12-31 06:16:51 · 13 answers · asked by Anonymous

In all my higher physics textbooks, the U.K mains voltage is quoted as being 230V. However, I had always thought that it was 240V. Who is correct?

2007-12-31 06:15:51 · 12 answers · asked by robzr6 1

yes it is a cylinder and it jsut needs to tip over

2007-12-31 05:44:37 · 2 answers · asked by mcbenz 1

did the force act on the mass?

2007-12-31 05:04:46 · 4 answers · asked by C0D3T4LK3R 2

... east?

2007-12-31 05:01:04 · 3 answers · asked by C0D3T4LK3R 2

... meters per second squared. How long will it take the rocket to reach an altitude of 9.0 X 10^3 meters?

2007-12-31 04:45:11 · 2 answers · asked by C0D3T4LK3R 2

The student used the textbook formula, and derived their relative velocity w.

After that, the student used the calculator, and found that
cosh(artanh(v/c)) = 7, and
cosh(artanh(u/c)) = 11.

What is the value of
cosh(artanh(w/c))?

2007-12-31 04:29:13 · 2 answers · asked by Alexander 6

If you could break the law of physics, what would you do and why?

2007-12-31 04:08:20 · 3 answers · asked by skilled frycook 1

Very simply.
When Hubble looks at a star, it is literally looking into the past. Because light travels at a finite (and constant) speed, we observe things long after they actually happen.

The earth has been on its journey for 4.6 billion years.
So, if I point Hubble to a point where the earth would have been say 1 million years ago why can't I see it?

I know it has something to do with the relative position of the observer. And I know it something to do with causality... but can someone explain the physical law that governs WHY Hubble could not target earth sometime in the past?

2007-12-31 04:08:00 · 6 answers · asked by acyberwin 5

2007-12-31 03:59:56 · 4 answers · asked by dean 4

1) A 900kg car traveling at 105 km/h runs into a tree and comes to a stop in 700ms. what is the average force exerted on the tree?

2) A rocket mass 500kg is propelled vertically upwards by a motor producing a force of 7kN. What is its acceleration?

3) An artificial satellite is placed in a circular orbit with a peroid of 16.0 days around Larissa, a moon of neptune. An on-board altimeter measures the distance to the surface of Larissa to be 2500km, which is much greater than the radius of the moon. Estimate Larissa's mass.

Please show workings and the general equations used to work them out. Many thanks in advance

2007-12-31 03:48:26 · 2 answers · asked by marc e 1

2007-12-31 03:43:23 · 7 answers · asked by Turgut y 1

2007-12-31 03:38:00 · 4 answers · asked by dean 4

If this was Possible, theoretically people would see you upside down right? I am thinking two dimensionally.

2007-12-31 03:06:22 · 6 answers · asked by Anonymous

If a photon had any mass, and mass increases to infinity at the speed of light (c), the entire universe would be one big photon...well, maybe it is... :o)

2007-12-31 02:53:54 · 2 answers · asked by Dino 1

energy come from? To give a non magnetic example, if I lift an object away from the Earth, I have stored up potential energy which I can release by letting it fall. In that case, the energy released by the falling object was originally provided by me when I lifted it. Now if I take two magnets, from two different sources (ie. I never pulled them apart) and lay them close enough together on a flat surface, when they get close enough they will of course move towards each other. So my question is, the where did that potential energy (which becomes kinetic energy as they move together) come from?

2007-12-31 02:29:00 · 6 answers · asked by Anonymous

what shape does H2O form?Is it terhedral due to the two lone pairs? This rule cannot be aplied to all molecules.

2007-12-31 02:25:43 · 1 answers · asked by Anonymous

2007-12-31 02:14:32 · 4 answers · asked by Anonymous

Consider a gold nucleus and an alpha particle. They exert an electrostatic repulsive force F on each other and are separated by distance r. The particle and the nucleus are being treated as point charges. when r = 5x10^-14m, F= 16N, and when r = 20x10^-14m, F = 1N. Use this information to calculate the values of the forces at distances r = 10x10^-14m and 15x10^-14m.

I'm really stuck on this one, can anyone help?

2007-12-31 01:53:34 · 5 answers · asked by Anonymous

http://en.wikipedia.org/wiki/SMOT

I know it doesn't work, I know there is no such thing as free energy but what is the actual practical reason why smots don't work.

Gravity wheels and such have been shown why they really don't work, but I still haven't seen anyone explain why a smot fails.

2007-12-31 01:38:09 · 6 answers · asked by worried person 1

If the moon can make the tides then is it possible to make some sort of device that makes little particles move by the moon's gravity?

This probably sounds conufsing but I am talking about some sort of gravity detector, detecting the small movement of particles(or something bigger) caused by the moon's gravity.

2007-12-31 01:22:46 · 2 answers · asked by worried person 1

If I put my finger and a 9V battery in a cup of water, what will the result be? Just a shock? Unconsciousness? Death?

I was thinking of trying something like that but don't want to do something like that just for fun if it's dangerous. 9V-testing on the tongue doesn't kill a person, so it shouldn't either on a wet skin, right?

2007-12-31 00:49:37 · 9 answers · asked by XB 3

2007-12-30 23:37:54 · 9 answers · asked by Anonymous

What is the advantage over the earlier methods?

2007-12-30 23:36:44 · 5 answers · asked by P.Anbil Prabu 1

2007-12-30 23:22:02 · 8 answers · asked by Grateful 1

2007-12-30 23:17:49 · 7 answers · asked by Anonymous

this has to do with laten heat.. I tried using Q= mL
do I just do (16.50)(3.33x10^5 J/kg) and ignore the initial temperature? where 16.50 is the mass and 3.33x10^5 is the heat of fusion?
I got 5.0 x 10^6
thanks.

2007-12-30 22:53:29 · 4 answers · asked by Anonymous