Physics - July 2007

A rocket ship in uniform flight has mass, velocity, momentum, and kinetic energy. It has the alien technology to be able to decrease its mass while maintaining its momentum. Does it take work to lose its mass, and, if so, how much work does it take to lose all of it and how fast it will then be going? Use relativistic momentum and energy, not Newtonian.

2007-07-28 05:06:44 · 3 answers · asked by Scythian1950 7

Can ever velocity & acceleration be "0"?

2007-07-28 04:22:45 · 11 answers · asked by rajesh bhowmick 2

2007-07-28 03:31:45 · 1 answers · asked by Spector 1

Could you help me find professional scientific forums on fluid mechanics AND energy recovery

2007-07-28 03:18:37 · 2 answers · asked by saeed f 1

It's been annoying me for ages!!! lol

2007-07-28 03:07:17 · 23 answers · asked by Bruza 17/uk 3

2007-07-28 01:47:39 · 6 answers · asked by bob b 2

According to current thinking (Big Bang, Relativity, String, etc.), at the "beginning" there was nothing. Then the universe expands, and Space and Time has meaning and existence only within that expanding universe. So,

Space is clearly not "nothing". What is it?

2007-07-28 01:43:31 · 8 answers · asked by café 1

2007-07-28 01:27:17 · 5 answers · asked by bob b 2

2007-07-28 00:18:30 · 5 answers · asked by Akilesh - Internet Undertaker 7

(exclude reflection and refraction)

2007-07-27 21:11:42 · 9 answers · asked by Anonymous

2007-07-27 20:04:41 · 3 answers · asked by Cat's Eye Angie 3

i had to leave school to support an ill parent and ...

2007-07-27 18:26:21 · 5 answers · asked by reedtexass 3

My friend told me that lightning does more damage when the ground near you is striked then when you are striked. I was wondering exactly why this was. I was also wondering, if it makes a difference to the effects on your body if you where on super turf ( fake grass) compared to real grass dirt or concrete. Also if you where holding a metal object when the ground near was struck by lightning what would happen?

2007-07-27 18:06:59 · 1 answers · asked by rebecca 2

2 airplanes, A & B are flying at the same altitude in the direction N30˚E and N10˚W. when B is 10km to the east of A, the pilots of both airplanes found that their planes are in the path of collision. If the speed of A is 500km h-1, find the speed of B. Give your answer to 3 significant figures. If at that point in time, B changes direction to N45˚W without changing its speed, find the closest distance between A & B.
(ANS:440 km h-1, 2.13 km)

2007-07-27 17:41:04 · 1 answers · asked by sonicdipsy 1

...what color would we perceive it as?

2007-07-27 17:06:42 · 5 answers · asked by Jay 4

When a rocket is moving in space and when it have to apply brakes or can say have slow down the velocity ,what is the mechanism?

2007-07-27 16:51:35 · 11 answers · asked by Anonymous

What would be the gravitational force between two golf balls (each with a 4.28 cm diameter), 1.15 meter apart, if they were made of nuclear matter?

This is the question I need to solve

I figure I need to use F = G * [(m*m)/r^2]

I know G is 6.67e-11
I figure r is 0.575m

but I'm having trouble finding the masses of the golf balls because I dont really understand nuclear matter

2007-07-27 16:25:23 · 5 answers · asked by rolo_cakes 2

2007-07-27 16:05:11 · 1 answers · asked by Darla T 1

what is mean by direct heated emitters & indirect heated emitters.how it is called when we combine both the direct & indirect heated emitters? & give me any more detail information about the both the emitters.

2007-07-27 15:25:00 · 1 answers · asked by priya d 1

What is the longest it has lasted for you or what is the average length?

2007-07-27 15:09:25 · 3 answers · asked by darcyaf1 3

The speed of microwaves is 3 x 10^8 m/s and their wavelength is 3x10^-2 m. Calculate their frequency..

9 x 10^6 Hz
1 x 10^-10 Hz
4 x 10^8 Hz
1 x 10^10 Hz

Which one is answer?

2007-07-27 14:58:46 · 4 answers · asked by Chikita 1

lie in the plane of greenwich meridian and are tangent to the surface of Earth one at north pole, and the other at south pole.

What is the angle between their trajectories at infinity?
(Ignore rotation of Earth)

2007-07-27 10:46:10 · 6 answers · asked by Alexander 6

I know some of the properties of light from studying and my own ideas, but I don't know what it is, just some of the properties. I would like to know exactly how charge and light (Em radiation) work together. I know that charge on the electron can absorb quanta of light, but I don't know how the light acts three dimensional in waves of magnetism and light, it seems to be a layered effect because charge turns into magnetism when in motion and vice versa. I see some other things, but I don't know how to describe them. I've only learned some trigonometry about the sine wave and the pythagorean identities, but I haven't ventured in enough to understand 3D waves or electromagnetism.

2007-07-27 10:25:03 · 3 answers · asked by Anonymous

2007-07-27 10:08:48 · 10 answers · asked by ballineagles 1

say there was like huge 30 foot red clock and in the middle of the night, one person stands 20 feet away, and the other goes 60 miles away (in the desert), gets a pair of binoculars and looks at the red letters of the clock...They are talking on a cell phone....will they both see different times? since it'll take the light a longer time to take to see?

2007-07-27 10:08:05 · 5 answers · asked by erwafredsfdsfsdf 5

My question is how did it regroup?

2007-07-27 09:55:51 · 5 answers · asked by Calvin & Hobbes 4

Any movement, corporation or set of corporations (conglomerate) with a single prominent leader that proposes a significant new knowledge, say with an inspiration from some traditional culture, is necessarily a cult. The leader is necessarily a pseudo scientific guru. Any attempt to connect their knowledge to some well known scientific theory is necessarily pseudoscience.

By new knowledge, I mean a structured knowledge with components that are provided with the intention to support each other. Also, the existence of a prominent leader is important. Organizations such as Yahoo inc. or Google inc. would not fit at all the above criteria.

I just asked almost the same question in General - Science & Mathematics. I hope it is not a duplication. I think that physicists are the most concerned.

Can you provide any possible exception to this criteria, even in principle? The idea is that, if no exception is provided, even in principle, then it is the criteria used by people.

2007-07-27 09:35:37 · 5 answers · asked by My account has been compromised 2

A partifcle of mass 34g and charge 19 uC is released from rest when it is 70 cm from a second particls of charge -19 uC. Determine the magnitude of the initial acceleration of the 34g particle. Answer in units of m/s^2.

2007-07-27 09:07:04 · 2 answers · asked by jay b 1

Hey, I'm struggling on a couple of physics questions regarding radioactive decay, if you could help me out that'd be great

1. The radioactive isotope 198Au has a half-life of 64.8 hr. A sample containing this isotope has an initial activity (t = 0) of 40.0 µCi. Calculate the number of nuclei that decay in the time interval between t1 = 10.0 hr and t2 = 12.0 hr.

2. In a piece of rock from the Moon, the 87Rb content is assayed to be 1.81×1010 atoms per gram of material, and the 87Sr content is found to be 1.06×109 atoms per gram. Calculate the age (in years) of the rock. Do not enter unit. 87Rb decays to 87Sr by beta decay with a half life of 4.75×1010 years.

Any help would be much appreciated.

Thanks

2007-07-27 09:03:50 · 2 answers · asked by rolo_cakes 2

2007-07-27 07:50:42 · 6 answers · asked by bikejon 1