Physics - February 2007

How can I calculate the amount of input force I would need with each turn of the handle and the total amount of force to raise the books with the distance of 20 cm.
the handle has a circumference of 150 cm., the pitch is 2 cm. and the books weigh 10 kg.
would it be F=2pir or W*P/2pir
If i used a pulley system using the same books which one of these machines will have greatest mechanical advantage.

2007-02-03 13:39:06 · 1 answers · asked by ghettoco 1

Why does the magnitude of current depend on potential difference (i.e. - greater potential, greater current)?

- I understand that current is the rate at which charge passes through a conductor.
-And, I understand that the potential difference is the basically how much work (energy) per unit charge is needed to move a charge from one point to another.

But, is there an explanation as to why greater potential difference means greater current?

2007-02-03 13:29:49 · 3 answers · asked by on_the_bb 2

2007-02-03 13:16:46 · 5 answers · asked by shamrock 1

A 2.50*10^2-kg cast-iron car engine contains water as a coolant. Suppose that the engine's temperature is 35.0º Celsius when it is shut off, and the air temperature is 10.0º Celsius. The heat given off by the engine and water in it as they cool to air temperature is 4.40*10^6 Joules. What mass of water is used to cool the engine?

Please help me with this problem.
I'm having trouble understanding this.

2007-02-03 12:51:23 · 1 answers · asked by swimmertommy 1

How does the winding action charge the battery or mechanism inside to allow the light to illuminate?

2007-02-03 12:35:47 · 7 answers · asked by Sunny2000 1

2007-02-03 12:35:17 · 4 answers · asked by turtlesoup331 1

I am wondering...Why is it more preferable for a household electric tea kettle to have a polished body? (Answer is supposed to be in terms of thermal energy).

Thanks!

2007-02-03 12:25:51 · 1 answers · asked by Anonymous

I need a good University for Astro Physics that is hard and no where near California. Any ideas??

2007-02-03 12:25:05 · 2 answers · asked by Anonymous

Was God thinking to himself when he said "let there be light" or did he actually say it to be heard? Which one enhances the other and in which order did it occur? Is there a measure of equivelence to sound verses light? In the beginings of creation, was there a sound that became as light was projected as witness upon the initial happening of something new? Was it simultaneios?

2007-02-03 12:18:39 · 3 answers · asked by Anonymous

in the military

2007-02-03 12:18:01 · 2 answers · asked by bulldog 2

1)Does the principal of linear superposition imply tht two sounds wave passing through the same place at the same time always create louder sound either a wave alone?

2)At an open air rock rock concert the music is played through the speakers tht r on the stage.the speaker point straight forward and nt toward the side.u r wandering abt and notice tht the sound of female vocalists can be hear infront of the satge bt nt off to the side. The rhythmic bass however can be hear both infront of the stage and off to the side. How does the phenomenon diffracting.

3)A tension in the guitar string is doubled. Does the frequency of oscillation also doubled?if nt by wht factor does the frequency change?specify whether the change is increase or decrese.

4)A turning forks has frequency of 440 hz the string of violin and this turning fork whn sounded together produce a beat frequency of 1 hz. From this two pice of information alone is it possible to determine the exact frequency of violin str

2007-02-03 11:59:34 · 3 answers · asked by Kshitil 1

2007-02-03 11:41:16 · 12 answers · asked by philip s 1

i think it boils at 100 degrees in F but what is that in C?

2007-02-03 11:40:30 · 12 answers · asked by jessica :] 5

...just wondered what would happen if you were able to manufacture an enclosed metal container that magnetically had a positive charge within it's entire interior wall...and could hold it's structural integrity. Lets say it weighed 50 lbs. in total.
...and then....could you have within this object a metal ball ALSO of positive charge...smaller, of course, and weighing perhaps 5 lbs. As far as I understand, "like-charged" objects will magnetically repel each other...meaning the central object should be in a state of levitation within the larger container...with both inner wall and object having positive charges.
The REAL question is this....if one were to weigh the container with this object within (hovering presumably), would it weigh in at 55 lbs. (the weight of both), or will it weigh in at 50 lbs...just the weight of the container???....since the inner object is effectively levitating?

2007-02-03 11:24:04 · 9 answers · asked by bradxschuman 6

Put the end of a capillary tube and the miniscus pulls the water a distance up the tube. This increases the potential energy of the water without any visible outlay of energy, right? If the water came over the top of the tube in this way, could it not drive a tiny turbine? With enough of these, could we not generate infinite electricity? Where is the flaw in this plan?

2007-02-03 11:12:00 · 4 answers · asked by Anonymous

I am totally confused about these two problems. I don't even know where to begin. I have spent 2 days trying to solve these two problems. Some one please Helpppppppppp immediately.

1. A 60.0kg mass is suspended from a rope which is threaded over a mass less pulley and then attached to a hook on a vertical wall. Draw or describe free-body diagram for the mass and another for the hook and show how each is in equilibrium. Calculate the tension in each part of the rope.


2 . Pulley A is suspended from a rope E, with one end of the rope attached to the ceiling and the other end threaded over pulley B. Pulley B is suspended from the ceiling with a rope G. From pulley A a 60.0kg mass is suspended with a rope F. At the end of the rope E threaded over pulley B is a mass m which keeps the system in balance.

2007-02-03 11:07:47 · 2 answers · asked by Anonymous

i need to know what gold bonds with well.
or what it does not bond with well.

2007-02-03 10:59:42 · 1 answers · asked by Anonymous

Who was the most important scientist for you ?

For me it will remain Tesla for ever..
and the Ether exists..

2007-02-03 10:53:27 · 10 answers · asked by kural_akhi 1

To pull a wagon across a lawn at a constant velocity you must exert a steady force. Reconcile this fact with Newtons first law which states that motion with a constant velocity indicates no force

2007-02-03 10:43:26 · 3 answers · asked by Bayslappers 1

and while we're at it what is the CT for absolute green? Currently I am under the impression that Green and magenta do not appear in the black body radiation scale because it never glows those colors - i'm just lost in this middle area... can anyone help?

2007-02-03 10:34:52 · 2 answers · asked by Pneurbies 2

2007-02-03 10:34:19 · 9 answers · asked by Shameka G 1

In the orbiting space shuttle you are handed two identical closed boxes one filled with sand the other with feathers. How can you tell which is which without opening the boxes

2007-02-03 10:26:18 · 6 answers · asked by Anonymous

2007-02-03 09:39:29 · 4 answers · asked by Anonymous

(a) Find the potential at points a and b in the figure below for charges Q1 = + 1.00 nC and Q2 = - 1.00 nC.
(Point A is 5cm from Q1, Q1 is 5cm from point B and point B is 5cm from Q2)
(b) How much work must be done by an external agent to bring a point charge q from infinity to point b?

I can get Va and Vb, I can't get the work done.

2007-02-03 09:39:25 · 2 answers · asked by David S 2

If a plane was flying from Heathrow to JFK, the current flying time is 7 to 8 hours at approx 5- 600 mph.
Since the Earth rotates west to east at approx 1000mph, could a plane fly to the correct latitude and fly in a holding pattern whilst it waits on JFK to appear over the horizon?
Assuming this could be done, would it speed the route up?

2007-02-03 09:27:56 · 8 answers · asked by Anonymous

2007-02-03 09:23:18 · 4 answers · asked by Melissa 2

Assuming a Trans Atlantic plane was allowed to fly straight across the Atlantic, I know about the engine thing and 500 miles from Iceland.
Anyway, would the curvature of the earth cause the plane flying straight between these two points to travel further out from the earth befroe turning back, thus travelling further than if it had travelled via the current route and thus travelling diagonally across the curvature of the earth.

2007-02-03 08:59:07 · 6 answers · asked by Anonymous

how can i connect a circuit to prove my point

2007-02-03 08:57:47 · 11 answers · asked by slick_chick 2

Copenhagen, MWI, Bohm's implicate order, etc.

And references, please, if you have them...

2007-02-03 08:55:09 · 2 answers · asked by Anonymous

2007-02-03 08:51:55 · 3 answers · asked by sunny p 1