Physics - November 2007

How does a thermos bottle minimize heat transfer? Investigate how heat loss due to convection, conduction, and radiation is prevented by looking at the design of a thermos. Compare cheaper versions to the design of more expensive versions and explain the differences in terms of the concepts used in the mechanism of heat transfer.

2007-11-25 23:49:11 · 6 answers · asked by ThE LaST HoRcRuX 3

2007-11-25 23:48:37 · 8 answers · asked by Anonymous

An aircraft flying horizontally at 360kmph releases a bomb at a stationary tank 200m away.What must be the height of the aircraft above the tank if the bomb is to hit the tank?

2007-11-25 23:34:33 · 3 answers · asked by anil p 1

2007-11-25 23:30:09 · 1 answers · asked by Krish 1

An ideal spring with a spring constant of 15 N/m is suspended vertically. A body of mass 0.60 kg is attached to the unstretched spring and released. a.) what is the extension of the spring when the speed is a maximum? b.) What is the maximum speed?

2007-11-25 23:23:01 · 4 answers · asked by kaynaptx 1

,copper into fine wires, diamond to cut glass, and clay to be molded into different shapes?
site other matter that exhibit special properties..
-answer this as soon as possible..
thank you!

2007-11-25 23:05:55 · 1 answers · asked by yuu hayashi 1

please answer this as soon as possible!
thanks a lot!
godbless..

2007-11-25 22:53:37 · 7 answers · asked by yuu hayashi 1

A 11.0 g bullet is fired horizontally into a 103 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring having spring constant 147 N/m. The bullet becomes embedded in the block. If the bullet-block system compresses the spring by a maximum of 84.0 cm, what was the speed of the bullet at impact with the block?
m/s

2007-11-25 20:04:45 · 3 answers · asked by AmandaLiu 1

E = mc^2 seems to have to do with time dilation for a mass traveling at the speed of light. Does the square for the speed of light apply when traveling at the speed of light in space?

2007-11-25 19:58:00 · 6 answers · asked by Dan 3

When an electron moves with a certain de Broglie wavelength, does the electron shake back and forth or up and down at that wavelength?

2007-11-25 19:06:48 · 4 answers · asked by Nomad 1

To come back to my question of yesterday, here is a page that claim the hydrosonic pump can output over 150% of the input energy. There is even some examples running for a year now in Georgia USA. Is this some scam or can it be real according to physics?
http://www.alternativescience.com/over-unity.htm

2007-11-25 18:49:21 · 4 answers · asked by Jan 3

2007-11-25 18:49:04 · 5 answers · asked by KrishanRam(Jitendra k) 3

If U = 3.85 x 10^-7
q1 = 5.0x10^-9
q2 = -3.0x10^-9
r12 = 0.35m

What is the electric potiential at a point midway b/w the charged particles?

I Just want to know how to do the method in solving the problem. An numberical answer is not required.

2007-11-25 18:46:18 · 2 answers · asked by Anonymous

Once the object has gained a certain velocity from any of the current methods currently being used, are there materials in space itself that the object could gather and somehow convert into energy for further propulsion to either increase speed or store it to be used later? Anyone aware of any ideas along this line?

2007-11-25 18:28:51 · 3 answers · asked by bush l 1

A particle with charge +q is at the origin. A particle with -2q us at x=2.00m on the x-axis.
a) What finite values of x is the elextric field zero?
b) What finite values of x is the electric potential zero?

2007-11-25 18:27:14 · 2 answers · asked by Anonymous

now imagine theres a point A at height of 40 metres . now from that point a thin non elastic lace (thread) starts to materialize(magically orignate) and run down and hits the ground due to gravity. the lace keeps on appearing and its like endless. now when it appears at point A its velocity is zero but it gets jerked up to a velocity . now what would be the vellocity of the lace when hits the ground after runnin down 40 metres. AIR RESISTANCE IS TAKEN AS ZERO. here gravity is acting on the vertical length of the lace which is forty metres. according to me the lace can have a maximum velocity of only 20 m/s. which is less than 28 m/s when u drop something from a height of 40 metres..

now for 1000 metres of lace (thread ) to run down originating from that point A, how long will it take..>? hope ppl get my question

2007-11-25 18:15:21 · 2 answers · asked by balaji.k 2

using words they would understand

2007-11-25 18:12:09 · 8 answers · asked by Anonymous

So my science teacher asked us for a formula to disprove going on a ship and walking forward and thus going faster then the speed of light, im thinking some formula where movement = 0 thus making it impossible, but not quite sure

2007-11-25 16:59:02 · 3 answers · asked by rjan 2

what did jj thompson do that contributed to the atomic theory

2007-11-25 16:26:10 · 4 answers · asked by bruke a 1

11-35) A thin rod of mass M and length l is suspended vertically from a frictionless pivot at its upper end. A mass, m, of putty traveling horizontally with a speed , v, strikes the rod at its CM and sticks here. How high does the bottom of the rod swing?

please help, thanks!

2007-11-25 16:19:24 · 1 answers · asked by Kiwikahuna 2

In the battle of the Falkland Islands in 1914, the shots of British gunners intially fell wide of their marks because their calculations were based on naval battles fought in the Northern Hemisphere. The Falklands are in the Southern Hemisphere. Explain the origin of their problem.

Please help, this question is from a physics textbook chapter 11 covering angular momentum and I've no idea how to answer it. Thanks!

2007-11-25 16:12:21 · 4 answers · asked by Kiwikahuna 2

(a) A hanging spring stretches by 35.0 cm when an object of mass 450 g is hung on it at rest. In this situation, we define its position as x = 0. The object is pulled down an additional 18 cm and released from rest to oscillate without friction. What is its position x at a time 84.4 s later?
______ cm
(b) A hanging spring stretches by 35.5 cm when an object of mass 440 g is hung on it at rest. We define this new position as x = 0. This object is also pulled down an additional 18 cm and released from rest to oscillate without friction. Find its position 84.4 s later.
______m
(c) Why are the answers to the parts (a) and (b) different by such a large percentage when the data are so simliar? Does this circumstance reveal a fundamental difficulty in calculating the future?

(d) Find the distance traveled by the vibrating object in part (a).
______m
(e) Find the distance traveled by the object in part (b).
_______ m

2007-11-25 15:58:02 · 1 answers · asked by thegenuwineone 2

A 0.329-kg puck, initially at rest on a frictionless horizontal surface, is struck by a 0.222-kg puck that is intitially moving along the x-axis with a velocity of 2.24 m/s. After the collision, the 0.222-kg puck has a speed of 1.24 m/s at an angle of 24 degrees to the positive x-axis. (a) Determine the velocity of the 0.329-kg puck after the collision. (b) Find the fraction of the kinetic energy lost in the collision.

2007-11-25 15:43:52 · 2 answers · asked by grouchy187 2

Tony (of mass 55kg) coasts on his bicycle (of mass 5kg) at a constant speed of 5 m/s, carrying a 6kg pack. Tony throws his pack forward, in the direction of this motion, at 1 m/s relative to the speed of bicycle just before the throw. The initial momentum of the system (tony, bicycle, pack ) is 330 kg* m/s. The momentum of the system after the pack is thrown is 330 kg*m/s.

What is the bicycle speed after the throw? answer in kg*m/s

2007-11-25 15:36:09 · 1 answers · asked by Light Up the Sky 1

A 12.0 kg block is dragged over a rough, horizontal surface by a 71.0 N force acting at 20.0° above the horizontal. The block is displaced 5.00 m, and the coefficient of kinetic friction is 0.300. What is the increase in internal energy of the block-surface system due to friction?

2007-11-25 14:49:47 · 1 answers · asked by Anonymous

Batman jumps straight down into a 500 kg. boat that is going 20 m/s while trying to catch a fleeing villain. The boat then slows to 17 m/s. What is the mass of Batman?

2007-11-25 14:49:14 · 3 answers · asked by yummy_girlscout 1

why do matter and anti-matter annihilate eachother. take for example an electron/positron pair. the only difference in the 2 is the charge. why does that mean they would be converted entirely to energy when they come in contact.

2007-11-25 14:45:27 · 6 answers · asked by Anonymous

so out of the three types of pions one confuses me, π0. its make of an up quark and anti-up quark, or a down quark and an anti-down quark. how does that work? wouldnt they annihilate eachother.

2007-11-25 14:43:27 · 1 answers · asked by Anonymous

A 7.0 g bullet is fired into a 1.5 kg ballistic pendulum. The bullet emerges from the block with a speed of 200 m/s, and the block rises to a maximum height of 12.5 cm. Find the initial speed of the bullet.
m/s

2007-11-25 14:13:09 · 1 answers · asked by AmandaLiu 1

2007-11-25 13:50:47 · 1 answers · asked by tchoxi2000 1