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Physics - November 2006

[Selected]: All categories Science & Mathematics Physics

is there any violation of law of conservation of energy? any emission of e m waves?does the energy appear as magnetic field?

2006-11-04 18:49:53 · 3 answers · asked by RRB 1

write down the diffrentional eq. obeyrd by the field E and B Iin an electromagnetic wave
show ta\hat the eq. is satisfied by:
1)E = A (x+k t)
2)E = A (x - kt)...raise to power 10
3)E = A ln(x+kt)
in each of the above ...find the value of the constant k..(E and A are vector)

2006-11-04 17:45:55 · 1 answers · asked by Atul 1

Other than a scrapyard crane

2006-11-04 17:28:11 · 7 answers · asked by Anonymous

2006-11-04 16:34:33 · 3 answers · asked by shailu_iitd 1

We know that silicon and germanium have four electrons in their valence shells and are used as semiconductors.Well Carbon too has four electrons in valence shell, in fact Ge and Si are of the carbon family, but we say that but for Graphite form, Carbon is an insulator ? why ?

2006-11-04 16:17:26 · 5 answers · asked by jan4all 1

perspective

2006-11-04 15:56:11 · 7 answers · asked by unni345 1

Cylindrical pulley w/ the following:
mass, M = 6.9 kg
radius, r = 0.811 m
moment of inertia 1/2 Mr^2

is used to lower a bucket (m=2.9 kg) into a well. The bucket starts from rest and falls for 3.3 s, acceleration of graviy is 9.8 m/s^2.

A) What is the linear acceleration of the falling bucket in units of m/s^2?

B) How far does it drop in units of m?

C) What is the angular acceleration of the cylinder in units of rad/s^2?

2006-11-04 15:05:09 · 2 answers · asked by Anonymous

I just have this h/w question, and it looks like it's really simple, I might just be missing something.

"A 0.22 calibre rifle shoots a bullet of mass 1.8g with a muzzle velocity of 500 m/s. If the barrel is 25cm long, what is the force exerted on the bullet while it is in the barrel?"

I know F=ma, I have the mass but not the acceleration, but i have the distance (25 cm=0.25 m) and the v1=500 m/s .... the answer is said to be 900 N, meaning that the acceleration would have to be 500 m/s^2 ... I dont understand how that makes sense... can anyone explain?

2006-11-04 14:42:38 · 3 answers · asked by ab237 1

the mass falls four meters than hits the spring which compresses another meter before coming to rest (temporarily)
Friction and air resistance can be ignored.

2006-11-04 14:20:02 · 3 answers · asked by webkng 1

don't neutrons act as glue to bond the prontons together since all the protons repel? so if the whole nucleus is tightly bonded, why do neutrons escape as radiation? and when they escape what kind of radiation do they escape as? gamma?

2006-11-04 13:11:22 · 7 answers · asked by Anonymous

I measured 94dB from an industrial sound source (4 ft away) in a very large room (guessing 200 x 400 ft with 20 ft ceilings). I am taking that same device and placing it in a 20 ft x 22 ft room with 10 ft ceilings. Most of that sound will come back as early reflections and that will increase the perceived sound by occupants of the room by some amount. I've looked into the physics books, and I seem to grasp the concept of the intensity varying 1/R^2. But I'm not sure exactly how to calculate the increase due to the volume of the room reduction. Not looking for a science project, just a quick & dirty guestimate! Please help!

2006-11-04 12:55:05 · 1 answers · asked by ian1972_pilot 2

Block 1, of mass "m1", moves across a frictionless surface with speed "vi". It collides elastically with block 2, of mass "m2", which is at rest (vi=0). After the collision, block 1 moves with speed "vf", while block 2 moves with speed "vf". Assume that m1 > m2, so that after the collision, the two objects move off in the direction of the first object before the collision.

1. This collision is elastic. What quantities, if any, are conserved in this collision?
-kinetic energy only
-momentum only
-kinetic energy and momentum

2. What is the final speed vf of block 1?
Express vf in terms of m1, m2, and vi.

3. What is the final speed vf of block 2?
Express vf in terms of m1, m2, and vi.

2006-11-04 12:46:33 · 2 answers · asked by Anonymous

in class our teacher was explaining newtons laws(or thought he was)and he said something about mu-mv\t and m1v1-m2v2 and something about explosions i didn't really get it so colud some1 pleeeease explain it for me

2006-11-04 12:37:58 · 4 answers · asked by shelly 3

I don't know how

2006-11-04 12:34:10 · 4 answers · asked by Anonymous

explain the difference between weight and mass. gracias. i think this is physics.. not sure though..

2006-11-04 12:00:24 · 12 answers · asked by Anonymous

You drop a 2.00 kg textbook to a friend who stands on the ground 10.0 m below the textbook with outstretched hands 1.50 m above the ground. (a) How much work W^grav is done on the textbook by the gravitational force as it drops to your friend’s hands? (b) What is the change ΔU in the gravitational potential energy of the text book – Earth system during the drop? Of the Gravitational potential energy U of that system is taken to be zero at ground level, what is U when the textbook (c) is released and (d) reaches the hands? Now take U to be 100 J at ground level and again find (e) W^grav (f) ΔU, (g) U at the release point, and (h) U at the hands. Explain your answers and clarify your work. Good Luck!!

2006-11-04 11:55:22 · 2 answers · asked by Anonymous

A merry-go-round rotates at the rate of 0.15 rev/s with an 85-kg man standing at a point 2.0 m from the axis of rotation.
(a) What is the new angular speed when the man walks to a point 0.7 m from the center? Assume that the merry-go-round is a solid 25-kg cylinder of radius 2.0 m.
in rad/sec
(b) Calculate the change in kinetic energy due to this movement.
in J

2006-11-04 11:37:20 · 1 answers · asked by activegirl 1

here is the question word for word along with answer choices. Keep in mind i already know the answer is letter b i just need to know how i get there.

An Olympic skier moving at 20m/s down a 30.0 degree slope encounters a region of wet snow and slides 145m before coming to a halt. What is the coefficient of friction between the skis and the snow?

a. 0.540 c. 0.116
b. 0.740 d. 0.470

So far with this problem i have found delta T and acceleration but i'm stuck.

2006-11-04 11:13:07 · 2 answers · asked by strawberrylollipop12345 1

Hello.

I am studying about Nuclear Energy, and relating it to CANDU reactors. I am having a hard time understanding the process within these CANDU reactors. IF anybody who knows about this reaction, or is an expert in the field, please give me a simplified explanation of the system, involving the uses of fuel rods, heavy water, normal,water, and control rods.

Thanks for reading.

2006-11-04 10:55:26 · 4 answers · asked by Xeel 1

If power costs, 8.0 cents/MJ, the cost(to the nearest dollar) to operate a 1500 W heater for 20 minutes a day for 300 days would be what amount of money?

2006-11-04 10:54:09 · 4 answers · asked by Kameliya 2

50N applied force is being pushed down on a 100kg block at an unknown angle (x). The coefficient of friction between the block and the ground is 0.4. regardless of the angle being used, what is the maximum elevation angle that will allow the 50N applied force to move the block? (image http://img296.imageshack.us/img296/7071/imagejq5.png)

2006-11-04 10:51:25 · 3 answers · asked by Anonymous

a balloon rises at a rate of 3 meters per second from a point on the ground 30 meters from an observer. find the rate of change of the angle of elevation of hte balloon from the observer when thte balloon is 30 meters above ground.

thank you.

2006-11-04 10:22:53 · 2 answers · asked by sandyclaws08 2

When scientists explain gravity like a ball sitting on a blanket and space forms a pit around it, shouldent that be incorrect. Isn't gravity all around earth and not just on a single plain? If this is so then the image that is generaly presented should be much more different.

2006-11-04 09:32:29 · 11 answers · asked by somerslats 2

I have a question I have been working on for a while about a the earth and the moon. I am supposed to find the total acceleration caused by the earth and moon at a certain point. I am given the mass of earth (5.98x10^24 kg) and the mass of the moon (7.36x10^22). The earth, moon and the point make up a triangle. The distance from earth to the moon is 3.84x10^8 m and the moon to the point is 1.48x10^8 m and the distance from the point to earth is 3.54x10^8 m. Also I have to find the magnitude of acceleration at this point. The last part is What is the total gravitational force on a spacecraft and the point? The mass of the spacecraft is 1200kg . What is the magnitude of the total gravitational force on the spacecraft.

If anyone can even steer me in the right direction it would help a lot...Thanks.

2006-11-04 09:19:47 · 5 answers · asked by Superman2332 1

An electric heater uses 12 amperes at 110 volts. If the cost of electricity is 13 cents per kWh, how much does it cost to operate the heater for 30.0 minutes a day for a month?

2006-11-04 08:36:24 · 3 answers · asked by Kameliya 2

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