Physics - July 2007

I am dring a car at constant speed, say 65 mph, on a freeway.
What Is the wind pressure on the car if
a. I close all the car windows.
b. I open one car window
c. I open all car windows.
I am trying to use as little gas as possible when driving .
Please explain or prove your answer. Thank you.

2007-07-05 07:52:14 · 4 answers · asked by buoisang 4

6. If you double the radius of the aluminum cylinder that was used in this lab, how much should the buoyancy force acting on it change (assume submerged in the same fluid)?

2007-07-05 07:23:04 · 3 answers · asked by NATTY 1

1. When solids are dissolved in a liquid the solid take up the spaces between the liquid molecules. If I have 2 containers and I dissolve 50grams of salt in one and 50 grams of sugar in the other, which container would provide your aluminum block with a greater buoyancy force (assume both completely dissolve)?
2. If quick sand is really just sand suspended in water would you expect a person to sink like they do in the movies? (Hint: you can think about this as if the sand was dissolved in the water to good approximation).

2007-07-05 07:22:31 · 2 answers · asked by NATTY 1

1.Suppose Spaceman Spiff flies his spaceship into Lake Superior on Wednesday, August 23rd 2000. The spaceship is 234 kg and, due to its air tight protective forcefield we can consider it to be a sphere (volume = (4/3)πR3). When Spaceman Spiff flies into Lake Superior he floats with only the small caution light floating (negligible mass) above the surface. What is circumference of the spaceship in cm? Remember that the circumference of a circle is 2πR.
2. Explain why fresh water boats can travel in the ocean while some ocean faring boats cannot travel in fresh water.
3. Suppose I give you an object that I say is made out of gold (density of 19.3 g/cm3). The object has a volume of 10mL and has a mass of 180 grams. Am I lying if say it is made out of solid gold?

2007-07-05 07:21:30 · 4 answers · asked by NATTY 1

I'm asking this because of the previous question about shooting bullets in the air. (2nd to last paragraph)

http://www.azcentral.com/news/articles/0702gl-gunfire0702-ON.html

There's a law against firing guns in the air. It's called Shannons Law.

2007-07-05 07:16:38 · 4 answers · asked by Anonymous

Simple question!

2007-07-05 07:10:50 · 6 answers · asked by Luke 1

How do they evacuate everyone and how fast does the radiation wave travel?

2007-07-05 07:09:39 · 2 answers · asked by ? 2

A block weighing 2 lb is forced against a horizontal spring of negligible mass, compressing the spring an amount x1 = 6 inches. Upon releasing the block, it moves on a horizontal table top a distance x2 = 2ft before coming to rest. The spring constant k is 8 lb/ft.

2007-07-05 07:06:44 · 2 answers · asked by Indecent 1

I am only young so please don't make it too complicated!

2007-07-05 06:40:29 · 3 answers · asked by JONATHAN 2

you might have noticed that while riding a bicycle when you apply the front brakes the cycle comes to rest almost instantaneously but when u apply the rear brakes the cycle does not come to rest quickly but skids for a short distance. WHY?

2007-07-05 06:28:55 · 4 answers · asked by prateek j 1

An orbital has many shapes like spherical,dumbbell etc.But,on what basis is the shape determined?

2007-07-05 06:21:24 · 4 answers · asked by Anonymous

Wein's displacement law says the peak wavelength is:
2900/5600 = 0.518 um = 518 nm (this is very green, see the table below)

I'm not convinced that it's due to atmospheric Rayleigh scattering, because the astronauts don't see a green sun do they?

I suppose it must be that sunlight has more red and orange than blue and violet, etc., so our eyes interpret this as yellow.

So if the "cones" in our eyes are essentially R-G-B, then, if G is stimulated, but R is more stimulated than B, does this appear yellow?

thanks.

color, wavelength interval
---------------------------------
red ~ 630–700 nm
orange ~ 590–630 nm
yellow ~ 560–590 nm
green ~ 490–560 nm
blue ~ 450–490 nm
violet ~ 400–450 nm

2007-07-05 05:59:53 · 7 answers · asked by Anonymous

2007-07-05 05:32:08 · 1 answers · asked by UMESH D 1

2007-07-05 05:24:05 · 9 answers · asked by Anonymous

In physics, what does "ground state vector" mean? Thanks!!

2007-07-05 05:21:49 · 2 answers · asked by Anonymous 1

a 10cm long thin rod uniformly charged to +10nC and a 10cm long thin rod uniformly charged to -10nC are 4cm apart. what are electric field strengths E1 to E3 at distances 1cm 2cm and 3cm from the glass rod along the line connecting the midpoints of the 2 rods? i know the formula for an infinite line of charge is E=1/(4*pi*epsilon 0) * 2L/r where epsilon 0=8.85e-12 or E=2KL/r where K=9.0e9.

2007-07-05 05:06:12 · 2 answers · asked by Nick48 2

through the center of the planet, and when
we have noon, they have midnight, right?

And if I jump into the tunnel and quickly exit
on the other side, will I move 12 hours
backward or forward in time?

2007-07-05 04:50:51 · 11 answers · asked by Alexander 6

If you open a tap in the kitchen and let the water fall into the sink, which already contains some water, you will sometimes see droplets of water fly up from the bowl. Are these droplets water from the tap bouncing back from the surface of the water in the bowl, water already in the bowl being displaced, or a mixture of both? Bearing in mind the height difference, is the answer the same when a similar thing happens when I (a male) sometimes pee into the toilet?

2007-07-05 04:47:56 · 7 answers · asked by Anonymous

When we place objects of different temperatures in a room, they usually come to the same temperature. But a damp object, even if it starts at room temperature, becomes cooler than the room. How does this play into the second law of thermodynamics?

2007-07-05 04:32:00 · 5 answers · asked by elliemae2891 1

Is there a technical difference between electric field and charge. Assume an electron is at the tip of a needle. Where is the charge?
a) on the electron
b) around the electron
c) the electron is the charge
d) everywhere in the space that surrounds the electron
e) the electric field and the charge are inseperable and are different ways of looking at the same 'electric thing'

2007-07-05 04:24:57 · 2 answers · asked by Mr Man 2

Momentum is inertia in motion, and is equal to the product of a body's mass and its velocity. For example, if the speed of a projected canonball is doubled, then the momentum is doubled. Or if instead the cannonball's mass is doubled, then the momentum is likewise doubled. Suppose however, that a cannonball's mass is somehow doubled and its velocity is also doubled. The its momentum is:

a) the same
b) doubled
c) quadrupled
d) none of these

Choose only one final answer (please!). A correct answer accompanied by a correct response trumps only a correct answer (or guess) alone. Good luck!

2007-07-05 03:56:08 · 7 answers · asked by ? 6

What I am trying to ask is. What is the speed of the person in the south direction as they head north in the plane.

2007-07-05 03:23:38 · 6 answers · asked by DNicolasL 2

2007-07-05 02:47:10 · 11 answers · asked by Anonymous

conservation of energy..
v know P.E = MGH.....AND k.e = 1/2 MV*V..

U TAKE a body of mass M TO a height H IT GAINS a potential of MGH.....

SAY if u can prove MGH > 1/2MV*V....otherwise....P.E > K.E...and that some of potential energy is not recovered.....and hence violating law of conservation of energy. .. what effect will it have on current physics...?? r how central is L.C.E....??

THANX..N CHEERS..

2007-07-05 02:44:12 · 4 answers · asked by breakfree ...... 2

Once again: As I continue to take pictures of my surroundings (within my house, specifically my bedroom), spheres of different sizes AND different colors continue to appear in the pictures. Some of them are incredibly brilliant, appearing as a bright light bulb against the background. When not as bright, one can actually see the inside of these forms that look like holes or craters within. I've been told these things could be: insects (no insects in my house), moisture (live in dry climate), faulty flash within the camers (have tried and use different cameras), lights from outside (no lights outside). Most significant is the fact that lately I have captured these "orbs/ odd formations" in movement: they produce a zigzag pattern which is easily detected due to the comet-like trail they leave behind while in motion. It is not dust either because not two pictures are alike while taken in sequence, each within 5 to 10 seconds of the other. Any ideas what these things are??

2007-07-05 02:40:30 · 11 answers · asked by Biancamaria S 2

Water is to be pumped to the top of the Empire State Building, which is 1200 ft high. What gauge pressure is needed in the water line at the base of the building to raise the water to this height?

i need this really bad...please help

2007-07-05 02:34:48 · 3 answers · asked by Anonymous

For safety in climbing, a mountaineer uses a nylon rope that is 56 m long and 1 cm in diameter. When supporting a 80-kg climber, the rope elongates 1.4 m. Find its Young's modulus.

for exam study...

2007-07-05 02:31:43 · 2 answers · asked by jojo21098 1

An ammeter and voltmeter of suitable ranges are to be used to measure the current and voltage of an electric lamp. If mistake were made and meters interchanged, what will happen?

2007-07-05 01:03:53 · 3 answers · asked by Anonymous

2007-07-05 00:59:08 · 4 answers · asked by Anonymous

2007-07-04 22:08:25 · 4 answers · asked by Apple 2