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Physics - March 2007

[Selected]: All categories Science & Mathematics Physics

John (75 Kg) and Jane (50 Kg) are friends since childhood. At a distance of 0.25 meters from each other, is their attraction
gravitational?

1. Box one answer (no explanations, necessary).

1. Yes
2. No

2. What is their attraction in Newtons?

2007-03-14 12:01:18 · 2 answers · asked by Lakers 1

What color is the cloth? Explain why it cannnot be any other color.

2007-03-14 12:00:53 · 3 answers · asked by Anonymous

How fast would super glue damage the brain if you were to hold it right under someones nose how low would thier IQ drop.
and could a bb traveling at a velocity of 750 fps go through a human skull.

2007-03-14 11:48:56 · 3 answers · asked by Anonymous

Calculate the quantity of heat energy needed to raise the temperature of a piece of aluminium.?
mass=3kg
temperature from 20degree celcius to150 degree celcius
specific heat capacity of aluminium=910 J kg-1 K-1

2007-03-14 11:34:33 · 4 answers · asked by lamide e 1

I have a science quiz on speed and velocity, you know, v=d/t?

Well I understand it, but only sort of, like I know it, but I can't think of it properly.

Can you give me any practice problems like finding time, distance or velocity? Like, 45 k/m h for 30 minutes?

2007-03-14 11:34:13 · 2 answers · asked by Addicted To Abercrombie & Fitch 2

... of 0.33 m and 0.6 m are seperated by a distance that is large compared to the diameters. The spheres are connected by a thin wire and are charged to 7.8 micro coulombs. The permittivitity of a vacuum is 8.85419*10^-12 C^2/Nm^2. What is the potential of the system of spheres when the reference potential is taken to be 0 at infinity. Answer in units of kV.

The thought I had for this problem was this: Initially, all the charge is in one sphere. After a while, the charge distributes itself, leaving the potentials on each sphere to be equal. After setting V1 equal to V2, you can solve for one of the charges which resides on one sphere. Following this, you can plug that number into the potential equation V = kq/r, with r being the radius of the sphere holding the charge previously found. Unfortunately, this isn't giving me the correct answer. Any help would be appreciated.

2007-03-14 11:19:32 · 3 answers · asked by mmrage318 1

As the solar panels suck the heat out of the Sun, will that pull more heat to concentrated areas of the earth? I like this to heat rays from a magnifying glass. We are concentrating where some of this energy goes. What happens when energy transfer is concentrated? What strength of force does this eventually lead to were it to grow? At what point would it be harmful to mankind?

2007-03-14 11:10:02 · 15 answers · asked by Anonymous

2007-03-14 11:09:34 · 6 answers · asked by Anonymous

a basket ball rolls of the rim and falls to the floor from a hiehg tof 3.05m. then it bounces up and loses 15% of its kinetic energy. To what height will it rise this time?...

my teacher explained it with 4 different equations but i dont get it...

2007-03-14 10:27:57 · 3 answers · asked by no name 1

Consider the circuit in Figure P20.46. Taking = 6.00 V, L = 3.00 mH, and R = 9.00 .

Figure P20.46
http://www.webassign.net/pse/p32-19.gif

(a) What is the inductive time constant of the circuit?
ms
(b) Calculate the current in the circuit 250 µs after the switch is closed.

2007-03-14 10:27:55 · 1 answers · asked by tiggerx313 1

1.) Due to thefts, only certain weights are available at one town's public gym. A weightlifter loads 20 lb on one end of the rod, and 50 lb on the other end. The rod itself is of uniform construction, 2 m long, weighing 15 lb. About equally distant from which point should his spotter ask him to grip so that the net torque on the weightlifter is zero, and the rod remains absolutely horizontal all through the pumping process?

2007-03-14 10:25:47 · 2 answers · asked by Tyler D 1

1.) the uniform door to a bank vault is 2.0 m high and 1.0 m wide and is supported by frictionless hindges. To determine the door's mass, a person pushes against its free end with a constant force of 250 N always directed perpindicularly to its plane and finds that 1.5 s is needed to turn the door through 90 degrees. What is the doors mass?

2.) An object of mass (m) on a frictionless table is attatched to the end of a string that passes through a frictionless hole in the table. The object is moving in a circle radius (R) with the angular speed omega (w) when the string is pulled through the hole until the object's orbital radius is R/2
a.) What is the new angular speed if the object?
b.) How much work had to be done to pull the string?

2007-03-14 10:24:10 · 1 answers · asked by Tyler D 1

I need to make a cover page for my book on sound... I need some ideas, because I want to put a lot of effort into it. Insturments, notes microphones and bands (all relating to music) Is all I have but I need a better idea!!!!!!!

2007-03-14 10:23:48 · 5 answers · asked by browncow 1

ok im doing an egg drop project fpr a class and its due in 2 days i have to build some thing so the egg won't break when i drop it 25feet the container can only be 6 inches all around i need easy fast ideas that will work i would have done it alot sooner but i just got told by my group that i was in charge of building something while they did nothing and i just said ok so will you help me thanks

2007-03-14 10:19:08 · 17 answers · asked by Anonymous

A bullet was fired at a target 50 m away with a muzzle velocity of 300 m/s. If the barrel of the gun was horizontal, how far in cm below the level of the gun did the bullet
strike the target?

2007-03-14 10:16:06 · 3 answers · asked by chrisamethyst 4

1.) The evenly spaced 4 spoke wheel has a diameter of 1.2 m. Its rim has a mass of 12 kg, and each spoke has a mass of 1.0 kg. Find the moment of inertia of the wheel.

2.) The seat of an adjustable piano stool has the mass (m) and the moment of inetria (I). If the seat is given an initial angular speed ot omega (w) in such a direction that the seat rises and there is no friction, how much higher is the seat when it stops turning?

2007-03-14 10:15:36 · 2 answers · asked by Tyler D 1

Consider the circuit in Figure P20.46. Taking = 6.00 V, L = 3.00 mH, and R = 9.00 .

Figure P20.46
http://www.webassign.net/pse/p32-19.gif

(a) What is the inductive time constant of the circuit?
ms
(b) Calculate the current in the circuit 250 µs after the switch is closed.

2007-03-14 09:59:58 · 1 answers · asked by joe p 1

I need help with my project:I need to find information and examples on gamma rays in Physical science class.

2007-03-14 09:52:36 · 1 answers · asked by sarvinoz h 1

if i could travel faster than the speed of light then the things i saw would appear to be moving backward. it would appear i was traveling back in time but if i closed my eyes and light didn't exist how could time travel be possible . wouldn't the objects be in a different places as to what i seeing them . so i wouldn't really be moving back in time id just be seeing a rerun of my life and bumping into people that could't see me becasuse my lights in the past but matters in the future.... or am i crazy...

2007-03-14 09:47:44 · 8 answers · asked by Slamin the clam 2

If a charge of +3x10^-6 coulombs sets up an electric field what is the magnitude of the file 9 meters away and the directive of the field?

2007-03-14 09:40:25 · 1 answers · asked by barbercjb231 1

5. If 1 cubic meter of water is at the top of a reservoir. How fast can it be moving if it drops 100 meters to some electric turbines below? The density of water is 100 Kg/m^3)

6. What is the pressure at the depth of 100 meters of water?

2007-03-14 09:33:41 · 1 answers · asked by Kakak 1

3. A certain amount of gas is forced into a rigid container. What happens to its pressure as we double its temperature?

4. If a 0.2 cubic meter baloon is filled with Helium. What is the buoyant Force ( Density of Helium is 1.075 Kg/m^3 and the Density of air is 1.25 Kg/m^3)

2007-03-14 09:32:09 · 2 answers · asked by Kakak 1

Here is the link to the problem:

http://i152.photobucket.com/albums/s167/gt_badone/Ch.jpg

2007-03-14 09:17:33 · 1 answers · asked by gt_badone 1

http://www.newscientist.com/article/dn11376-photons-life-cycle-watched-in-full.html

Is there a way to stop the particles from blinking out of existence altogether?

2007-03-14 09:13:14 · 2 answers · asked by ? 2

A plane is flying level at 2000ft above the ground.
The plane is carrying a 500lb.
From the time the bomb is released to the time the bomb hits
the ground how far has the bomb traveled horizontally?
Air resistance is not a factor the ground is level.
Please state the equation that you used that produced your answer.
Im playing a combat flight simulator game and trying to figure out how far back i need to be from my targets.

2007-03-14 09:09:28 · 5 answers · asked by Truthasarous rex 3

Consider the circuit in Figure P20.46. Taking = 6.00 V, L = 3.00 mH, and R = 9.00 .

Figure P20.46
http://www.webassign.net/pse/p32-19.gif

(a) What is the inductive time constant of the circuit?
ms
(b) Calculate the current in the circuit 250 µs after the switch is closed.

A
(c) What is the value of the final steady-state current?
A
(d) How long does it take the current to reach 80% of its maximum value?
ms

2007-03-14 08:44:50 · 3 answers · asked by joe p 1

That is, initially the rock has a high potential energy. Then, its energy is converted into kinetic energy as it falls. So i understand energy is merely changing form.

But then it hits the ground. The rock ceases moving at a relative height of zero. Into what form was the enrgy converted? Is it converted into kinetic enrgy that travels through the particles of the ground? Thanks a lot!

2007-03-14 08:33:39 · 3 answers · asked by kmm4864990 1

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