Physics - February 2007

2.
Assuming a hypothetical planet to be a uniform sphere, of mass 3.0E24 kg, radius 5.0E6m and 1.4E8km from the sun.

a- estimate the kinetic energy of this hyphthetical plante due to its 24 hour rotation about its axis

b- estimate the kinetic energy of this hypothetical planet with respect to the sun due to its yearly 365 day revolution

c- estimate the kinetic energy of this hypothetical planet with respect to the sun as the sum of the kinetic energies resulting in part a and part b

2007-02-25 06:00:44 · 2 answers · asked by uglyshrek6 1

The past can affect the future, and the present can affect the future. I have heard this already, but can the future affect the past, and if so, how?

2007-02-25 05:53:55 · 4 answers · asked by The Ponderer 3

Is it possible to electronically convert different frequencies of light (different colors) into a forms that are audible? (ie. help the blind to see?)

2007-02-25 05:49:46 · 4 answers · asked by rgtheisen2003 4

Are spherical tokamaks the same as spheromaks? - I mean exactly the same; are they just two words meaning the exact same thing or are they two sepperate things?

2007-02-25 05:49:15 · 2 answers · asked by Anonymous

If I have a .22 inch dia bore by 19 inches long, and a projectile weight of 14 grains, and a constant pressure of 800 PSI. What would the muzzle velocity be for this projectile?

Specifically, I want to take the barrel off an old .22 LR rifle, and convert it for use with .22 caliber pellets using CO2 as a propellant. I'm not sure what the friction costs would be for this, but my calculations seemed to be between a .200 and .300 coefficient of friction (please correct me if I'm wrong, I'm sure of how the coefficient of friction is noted).

If you could please post the formula(s) that you used as well it would be appreciated.

So far I've got .038 sq in. with a pressure of 800 psi = 30 lbs of force. But that's where I'm stuck. I'm not sure how to calculate the acceleration when time is not known. I know distance (19 inches), but I don't know time.

Thanks!

2007-02-25 05:48:47 · 1 answers · asked by CJP 3

Boat coasts to a halt. Assume-contrary to fact-that the resistive force due to the water is constant, inderpendent of the boats speed. How far does the boat coast? How much time does it take for the boat to come to rest after the engine is turned off?

2007-02-25 05:07:36 · 2 answers · asked by katiexobean 1

In an EM wave traveling west, the B field oscillates vertically and has a frequency of 80.0 kHz and an rms strength of 6.75 X 10^-9 T. What are the frequency and rms strength of the electric field, and what is its direction?

2007-02-25 05:03:46 · 1 answers · asked by Anonymous

A block of mass m = 3.00 kg situated on a rough incline at an angle of = 37.0° is connected to a spring of negligible mass having a spring constant of 100 N/m. The pulley is frictionelss. The block is released from rest when the spring is unstretched. The block moves 14.5 cm down the incline before coming to rest. Find the coefficient of kinetic friction between block and incline.

2007-02-25 04:54:35 · 1 answers · asked by tnhoots 1

Hi, im doing my physics coursework revisit and i really need to to know how hard and soft surfaces can be used in a theatre.

Hard surfaces on the walls can be used to reflect sound right?
but what about soft surfaces?

2007-02-25 04:54:13 · 4 answers · asked by katie_orlandoarogorn 2

2007-02-25 04:50:12 · 11 answers · asked by David M 1

The string can be torn by a force exceeding the value of 10 Mg where g is acceleration due to gravity. The bead on the string may ocsillate harmonically with a period T0. a student decides to perform another experiment. he takes the attched nead aside from its equilibrium and pushes it in such a way that the bead performs a full revolution in a horizontal plane. What is the time of one revolution of the bead that can be calculated with the data, given above? is this time a maximum or a minimum value of all possible?

2007-02-25 04:49:30 · 1 answers · asked by star 1

I have recently returned from NZ and, experimenting, came to the conclusion that normally water goes down the plughole in the southern hemisphere in an anticlockwise direction. However I met a proffesor of physics who told me that this was a myth. In scotland it goes down in a clockwise direction.

2007-02-25 04:48:26 · 9 answers · asked by Tansy's dad 1

We've sent men to the moon, (though the conspiracy theorists may argue with that) we've sent remote probes to Mars, we've produced robots to make cars, and a million other technological marvels, but still we don't seem to be able to produce a supermarket trolley that you don't have to wrestle with to keep it going in the direction that's required.

What *is* the problem, guys?

P.S. I can't seem to find an appropriate category for this, so this one will have to do.

2007-02-25 04:39:07 · 5 answers · asked by Guru Nana 2

Is because vibrations called sound propagate from a medium to a medium and when they meet vacuum there is nothing to vibrate anymore?If so how do electrons and electromagnetic fields react to a sonic wave?Do they interfere?electrons and atoms can make sounds? OR SOUND IT 'S A PROPERTY OF MOLECULAR LEVEL WHILE ELECTROMAGNETIC WAVES ARE PROPERTY OF ATOMIC LEVELS?

2007-02-25 04:31:44 · 4 answers · asked by ParaskeveTuriya 4

2007-02-25 04:17:12 · 13 answers · asked by gumtrunk 2

2007-02-25 04:05:09 · 3 answers · asked by Anonymous

2007-02-25 03:56:35 · 4 answers · asked by Jessica W 1

2007-02-25 03:50:17 · 8 answers · asked by A 1

If you put a bell and a voice recorder inside such a box and remove the air, and shake well, will the voice recorder tape something, some sound?

But a person outside the box, in the kitchen,will hear anything?

Unfortunately I don't have one at home to make the experiment.

2007-02-25 03:49:56 · 1 answers · asked by ParaskeveTuriya 4

2007-02-25 03:36:41 · 2 answers · asked by sue m 2

Advanced math okay (wanted).

2007-02-25 03:36:13 · 4 answers · asked by CQ 3

2007-02-25 03:23:45 · 4 answers · asked by Jessica W 1

For instance: e = mc2
c, in inches
m, in pounds, then,
e, in BTU's?

Or is there people in America that knows the metric system ?

2007-02-25 03:21:10 · 2 answers · asked by QQ dri lu 4

2007-02-25 03:20:10 · 2 answers · asked by Jessica W 1

2007-02-25 03:18:43 · 3 answers · asked by Jessica W 1

2007-02-25 03:17:47 · 2 answers · asked by Jessica W 1

some places it is given as "1/f = 1/v - 1/u" , other places it is given as "1/f = 1/v + 1/u". which is true. Also, when to use which, and why is the negative sign there? in each formula, sign convention for the values substituted for each should be negatiev or positive ( with relation to image direction from lens or mirror, etc.,)

2007-02-25 03:05:58 · 1 answers · asked by Anonymous

If a postion vs. time plot is rising in time (but not in such a way as to produce a vertical line on the graph) then we can know for certain that ______________________________...

a) velocity is changing
b) velocity is constant
c)position is constant
d) acceleration is constant
e) acceleration is changing
f) it has a velocity <0 and velocity is changing
g) it has a velocity > 0 but we don't know if the velocity is constant
h) we can't know any of these

2007-02-25 02:54:55 · 3 answers · asked by Anonymous

the navigator of an airplane plans a flight 1200 km away, in a direction 30degrees E of N. he is informed of a prevailing wind from the west of 80 km/h. the pilot wants to maintain an air speed of 300km/h.
a) what heading should the navigator give the pilot?
the answer is 17degrees E of N
b) how long will the flight take?
the answer is 3.6 hours
c) how much time did the wind save?
the ans is 0.41 hours

thanks!!!

2007-02-25 02:51:15 · 1 answers · asked by Anonymous

Also what do mathematicians, researchers, physicist, and data analyst do?

2007-02-25 02:33:39 · 5 answers · asked by Anonymous