Physics - December 2006

Since looking into space is like looking into the past, the only way to exprience NOW is to be local in any relation in the Universe. For instance, the light from a galaxy 5 billion light years away is light from THEN; not light from NOW. So is 'now' local?

2006-12-01 05:05:58 · 9 answers · asked by Prince Auggie 2

2006-12-01 04:59:19 · 8 answers · asked by Anonymous

I know that quasars are one of the fartheset things we can see in space (10-13 billion light years away). So with that logic they are also some of the youngest things in the Unvierse. Does this mean this is how galaxies get their start?

2006-12-01 04:56:12 · 3 answers · asked by Prince Auggie 2

I have often heard that when a large ship sinks it sucks down any objects or survivors that may be floating near by. If this is the case what causes it. Or indeed is it because the escaping air from the sinking ship causes the water near buy to become less dense meaning the objects near by have aparently less boyancy.
JOHN

2006-12-01 04:41:36 · 13 answers · asked by g7bwi 1

A large globe, with a radius of about 5m , was built in Italy between 1982 and 1987. Imagine that such a globe has a radius R and a frictionless surface. A small block of mass m slides starts from rest at the very top of the globe and slides along the surface of the globe. The block leaves the surface of the globe when it reaches a height h above the ground.

Using Newton's 2nd law, find Vcrit, the speed of the block at the critical moment when the block leaves the surface of the globe.
1. Assume that the height at which the block leaves the surface of the globe is hcrit.
Express the speed in terms of R, hcrit, and g, the magnitude of the accleration due to gravity. Do not use in your answer theta.

2.Use the law of conservation of energy to find vcrit . This will give you a difference expression for than you found in the previous part.
Express in terms of R, h, and g.

3.Find the height from the ground at which the block leaves the surface of the globe. Expressin termsR

2006-12-01 04:30:00 · 2 answers · asked by Anonymous

2006-12-01 04:25:25 · 1 answers · asked by *fireflies* 2

I was looking at this problem when I began thinking about the relationship:

When electromagnetic radiation of
wavelength 300 nm falls on the surface
of sodium, electrons are emitted with a
kinetic energy of 1.68 ×105 J mol–1. What
is the minimum energy needed to remove
an electron from sodium? What is the
maximum wavelength that will cause a
photoelectron to be emitted ?

2006-12-01 04:19:35 · 4 answers · asked by ishisgreat 1

A girl pushes a box 300N at 2 m/s. She stops pushing the box and it comes to rest 3 seconds later. How large is the force of friction on the box?

A. 20 N
B. 50 N
C. 150 N
D. 200 N
E. 300 N

2006-12-01 04:03:26 · 4 answers · asked by James R 1

2006-12-01 03:45:30 · 8 answers · asked by Anonymous

2006-12-01 03:44:36 · 6 answers · asked by NAVEEN S 1

2006-12-01 03:42:42 · 4 answers · asked by Anonymous

Is it true to say that Einstein's special theory of relativity is based of the postulate thaat the sped of light is constant?

2006-12-01 03:38:34 · 4 answers · asked by Anonymous

The air pressure above the liquid in an open container is 1.12 atm. The depth of an air bubble in the liquid is 35.2 cm (measured from the middle of the air bubble to the top of the liquid). The liquid's density is 831 kg/m^3. Determine the air pressure in the bubble suspended in the liquid (in Pa). Acceleration of gravity is 9.8 m/s^2.

My ans. thus far that are WRONG:
127167 Pa
114300 Pa
116.353 Pa

2006-12-01 03:34:26 · 3 answers · asked by Mariska 2

2006-12-01 03:27:47 · 2 answers · asked by baby 1

2006-12-01 03:22:59 · 3 answers · asked by Anonymous

2006-12-01 03:15:15 · 3 answers · asked by yo yo ma 2

A planet with radius of 6.25 * 10^6 m has a mass of 5.95 * 10^24 kg, its moon has a mass of 7.43 * 10^22 kg, and their center-to-center distance is 3.75 * 108 m. (As the planet and moon orbit one another, their centers orbit about their common center of mass.)
How far from the center of the planet is the planet-moon center of mass?
Is the planet-moon center of mass above or below the surface of the planet?
By what distance?

Alright, my professor hasnt really gone over anything in class that has to do with any of this. Just thinking about it, it would seem that the center of the planet would be the center of mass, so the distance for the first question would be 0. For the second question, i know that it would be below the surface of the planet. Finally, for the 3rd question, if the center of mass was the center of the planet, wouldnt the distance just be the radius? I dont believe this is right though, seems too easy

2006-12-01 02:56:13 · 1 answers · asked by matt b 1

2006-12-01 02:55:58 · 12 answers · asked by yo yo ma 2

Can anyone explain why Schrodinger has a zombie cat wandering around the Universe? I'm not certain about this. But what did he have against cats anyway!

2006-12-01 02:21:49 · 8 answers · asked by Anonymous

2006-12-01 01:53:12 · 7 answers · asked by Benjamin A 1

2006-12-01 01:35:16 · 3 answers · asked by supersup66 1

2006-12-01 01:34:44 · 17 answers · asked by felsztukier 1

Military specs oftan call for electronic devices to be able to withstand accelerations of 10 g. To make sure that they do, manufacturers test them using a shaking table that can vibrate a device at various specified frequencies & amplitudes. If a device is given a vibration of amplitude 9.7 cm, what should its frequency be in order to test for compliance with the 10 g requirement (ans in Hz)?

d = v*t + 0.5*a*t^2 = 9.7sin(x*t)
take the derivative
v + a*t = 9.7x*cos(x*t)
take the derivative
a = 9.7*x^2*-sin(x*t)

so:
10g = 9.7*x^2
x^2 = 10*9.8/9.7
x = 10.1

2pi = 10.1*T
T = 0.62 sec

freq = 1/T
freq = 1/0.62
freq = 1.61 Hz

2006-12-01 00:55:37 · 2 answers · asked by Mariska 2

These two elements seem to be exceptions to the larger rule that atoms with an odd number of electrons are paramagnetic and elements with an even number of electrons are diamagnetic. If anyone knows, or better, knows a good place I could read about this, that would be wonderful. My electromagnetic theory book doesn't say why this is, only that it is. Thanks!

2006-12-01 00:54:24 · 3 answers · asked by benjamin s 1

2006-12-01 00:47:59 · 3 answers · asked by Anonymous

A lunch tray is being held in one hand. The mass of the tray itself is 0.300 kg, and its center of gravity is located at its geometrical center. On the tray is a 1.00 kg plate of food and a 0.205 kg cup of coffee. The distance from the cup to the hand is 0.400 m, the distance from the center of the cup to the hand is 0.380 m, the distance from the center of the plate of food to the hand is 0.240 m, the distance from the tip of the four finger at the bottom of the lunch tray to the above thumb is 0.100 m, the distance from tip of the thumb to the palm of the hand is 0.0600 m.

Obtain the force T (downward)exerted by the thumb and the force F (upward) exerted by the four fingers. Both forces act perpendicular to the tray, which is being held parallel to the ground.

2006-12-01 00:43:31 · 4 answers · asked by Alan l 1

2006-12-01 00:42:21 · 8 answers · asked by [keepitdk] 1

2006-12-01 00:38:15 · 9 answers · asked by sweet angels 2

A rotating merry go round makes one complete revolution in 4.0s. a) What is the linear speed of a child seated 1.2m from the center? What is her acceleration(give components)?

2006-12-01 00:33:10 · 2 answers · asked by Anonymous

in mercury the last orbital?

2006-12-01 00:22:01 · 2 answers · asked by hemanth_b4u1 1