Physics - November 2007

The magnitude of the Earth's magnetic field at either pole is approximately 7.99*10^-5 T. Suppose the field fades away, before its next reversal. Scouts, sailors, and conservative politicians around the world join together in a program to replace the field. One plan is to use a current loop around the equator, without relying on magnetization of any materials inside the Earth. Determine the current that would generate such a field if this plan were carried out. Tak the radius of the Earth as R_e = 6.37*10^6 m.

2007-11-30 21:17:52 · 1 answers · asked by andrew w 1

2007-11-30 21:10:37 · 6 answers · asked by Sean 3

Such as seeing into the future, or reaching hot temperatures etc.

2007-11-30 21:06:11 · 15 answers · asked by Anonymous

a.) what pressure does the cylinder exert on the floor?
b.) if it is filled with water, what is the total force at the bottom?
c.) find the total force at the walls of the container.

2007-11-30 20:05:08 · 3 answers · asked by enchanted 3

A 94.0 N grocery cart is pushed 12.0 m along an aisle by a shopper who exerts a constant horizontal force of 40.0 N. If all frictional forces are neglected and the cart starts from rest, what is the grocery cart's final speed?
m/s

2007-11-30 17:25:42 · 3 answers · asked by NiNi 2

2007-11-30 16:46:00 · 2 answers · asked by evenstar03 2

According to Bohr, can a single electron in one excited state give off more than one photon when it jumps to a lower energy state?

2007-11-30 16:42:25 · 1 answers · asked by evenstar03 2

a student pushes a 0.85-kg textbook across a cafeteria table toward a friend. As soon as the student withdraws the hand (the force is remobed), the book starts slowing down, coming to a stop after moving 65 cm horizontally. The coefficient of kinetic friction between the surfaces in contact is 0.38.

a) how do i draw a system diagram and an FBD diagram of the book as it slows down and calculate the magnitudes of all forces in the diagram.

b) Calculate the work done on the book by the friction of the table.


thanks for any help!

2007-11-30 15:46:03 · 2 answers · asked by E=MC^2 1

2007-11-30 15:40:25 · 1 answers · asked by Anonymous

A heat engine operates between a high-temperature reservoir at 610 K and a low temperature reservoir at 320 K. In one cycle, the engine absorbs 6400 J of heat from the high temperature reservoir and does 2200J of work. What is the net change in entropy as a result of this cycle.

2007-11-30 15:04:56 · 2 answers · asked by Anonymous

How do you covert pressure (Pa) to pound per square inch

2007-11-30 14:28:25 · 1 answers · asked by SoRealistic 3

What mass of steam that is initially at 120 C is needed to warm 350g of water and its 300g aluminum container from 20 C to 50 C?

2007-11-30 14:25:44 · 2 answers · asked by Anonymous

Pressure and temperature? Volume and Temperature?

2007-11-30 14:21:13 · 2 answers · asked by Nizie 1

A home heating system can supply energy at the maximum rate of 26 kW. If the house loses energy at the rate of 6.5 kW per °C of temperature difference between interior and exterior, what's the minimum outdoor temperature at which the heating system can maintain 22°C (71.6°F) indoors?

2007-11-30 13:59:00 · 2 answers · asked by Anonymous

2007-11-30 13:47:54 · 13 answers · asked by dancingsmartypants 2

1. Do the resonance frequencies depend on the tension of the string?
2. Do the resonance frequencies depend on on the mass density of the string?
3. Do the resonance frequencies depended on the length of the string?
4. Two strings equal in length and made of the same material are sujected to tensions in the proportion of 1:4; the one under the greater tension is the thicker string. If they vibrate at the same frequency, how do their diameters compare?

2007-11-30 13:44:12 · 1 answers · asked by mokachi 1

what is tins density at room tempreature and its electron configuration

2007-11-30 13:03:29 · 1 answers · asked by Anonymous

Its well known that as one of two twins relatively approaches the speed of light, the age difference between both will become significant.

However, if one of them remains still relative to the earth and the other runs, say 10 meters, up and back, would there still be a small (even an attosecond) difference in the age of each twin?

2007-11-30 12:57:47 · 3 answers · asked by sal 1

An 75.0 N box of clothes is pulled 16.0 m up a 30.0° ramp by a force of 115 N that points along the ramp. If the coefficient of kinetic friction between the box and ramp is 0.22, calculate the change in the box's kinetic energy.

Show me how to plug in the numbers and what you did to find fnet

2007-11-30 12:47:06 · 4 answers · asked by Anonymous

2007-11-30 12:43:24 · 7 answers · asked by THAT girlll 1

A block of mass 3.7 kg is resting on a horizontal surface with a static coefficient of friction, µ=1.3. A spring with a constant 470 N/m is attached to the block and someone pulls on the other end of the spring. By how much does the spring extend before the block begins to move? g=9.81m/s2.

2007-11-30 12:10:30 · 2 answers · asked by A Saucerful of Secrets 2

Cats always land on their feet. Toast always lands buttered side down. So if I strap a slice of toast butter side up onto a cats back, I will have created an anti gravity device, correct?

Hold onto your hat, science. I'm about to blow your f*****g mind.

2007-11-30 11:08:39 · 8 answers · asked by Anonymous

Here's the full question:

If you are on the far side of the moon you are farther away from the earth than if you are on the near side. a.) What is the difference in your true weight between standing at the nearest and farthest surface positions on the moon relative to the center of the earth?

Well I think that you need to use Fg=(Gm1m2)/r^2
but what do you do with that? Perhaps add the force of gravity of the moon and the earth together? I'm not sure what to do. Thanks for the help.

2007-11-30 11:07:52 · 1 answers · asked by Anonymous

If a car speeding at 100mph on a highway crashes into the rear end of a car traveling at 60mph, would the impact be the same (or greater) as a car at 40 crashing into a stationary car? What does physics have to say about the difference? Thanks to all in advance for indulging me.

2007-11-30 10:57:33 · 3 answers · asked by eugmir 2

The sun has a mass of 1.99*10'30 kg, and is moving in a circular orbit around the center of our galaxy, the Milky way, dragging the rest of the solar system behing it. The radius of the orbit is 2.3*10'4 light years(1 ly=9.5*10'15)and the sun has an angular speed of 1.1*10'-15 rad/s. What is the magnitude of the net force keeping the sun moving on this path?

2007-11-30 09:52:26 · 3 answers · asked by Anonymous

An 90.0 N box of clothes is pulled 23.0 m up a 30.0° ramp by a force of 115 N that points along the ramp. If the coefficient of kinetic friction between the box and ramp is 0.22, calculate the change in the box's kinetic energy.

Just show me how you got it

2007-11-30 09:09:02 · 6 answers · asked by Anonymous

I was pretty sure there was a method for measuring the density of a solid by comparing the weight in water with the dry weight, but I cannot find exactly what conversion etc. to use or how to get the density using these weights.

2007-11-30 09:01:16 · 3 answers · asked by Justin 2

It's about the "rotating mass". I think at speed, they would be the same. The difference in acceleration not noticable.

2007-11-30 08:57:12 · 3 answers · asked by Anonymous

2007-11-30 08:36:36 · 4 answers · asked by Tanya L 2

A m=6 kg weight is dropped from height h =2.0 m onto a cart containing sand , mass M= 22 kg, initially moving at horizontal speed v= 3.1 m/s. How much heat is released in the process ?

2007-11-30 08:27:58 · 1 answers · asked by Anonymous