Physics - May 2007

In a classroom demonstration, the pressure inside a can is suddenly reduced to essentially zero. Assuming the can to be a cylinder with a height of 13 cm and a diameter of 43 cm, find the net inward force exerted on the vertical sides of the can due to atmospheric pressure.

The Surface Area of the cylinder is: 2pie(r^2)+2pie(r)(h).
The astmospheric pressure is: 1.01E5 Pa.

Should I just be using the P=F/A, P(A)=F?

2007-05-17 08:11:37 · 2 answers · asked by iheartdr.sambeckett 4

WE NEED THE ANSWERS NOW FOR CLASS

2007-05-17 08:09:18 · 6 answers · asked by Anonymous

If I am 60 years old and a time machine is invented and I go back in time to when I am 20 years old and stop a man from wrecking into my friend and killing him will my 20 year old self have to go back in time when he is 60 and continue to stop it, or do you only have to go back and alter time once?

2007-05-17 08:05:21 · 8 answers · asked by Anonymous

2007-05-17 07:38:20 · 4 answers · asked by $ iNdIaN TaChyOuN $ 1

we have read earlier that every matter has a pair so where is the earth pair.

2007-05-17 07:05:32 · 8 answers · asked by shaikh s 1

I don't know the formula for these. Is there just one, or a different formula for each? Thanks!

1. A simple machine exerts a resistance force of 1,000 N when an effort force of 250 N is applied. What is the machine's mechanial advantage?

2. The effort force of 250 N includes a friction force of 50 N that must overcome. If there were no friction, what would the ideal mechanical advantage of this machine have been?

3. The work input to a machine is 25 J and the work output is 5 J. What is the efficiency of the machine?

4. An object moving a a speed of 1m/s has a kinetic energy of 5 J. What is its kinetic energy when it moves at 3m/s?

5. Suppose an object 10 m above the ground had a potential energy of 5 J. What will its potential energy be if it is raised to 20 m above the ground?

6. An object has a potential energy of 100 J when it is 10 m above the ground. If it were to fall without friction, what would its kinetic energy be the instant before it hit the ground?

2007-05-17 06:58:56 · 1 answers · asked by JaNaLiEn 2

Why is it that all the fields in the Standard Model form either the trivial, fundamental, or adjoint representation of the gauge groups? It obviously makes sense to me why they should be irreducible representations, but why always these three? Does this suggest anything about the GUT or SUSY group these particles might form a representation of?

2007-05-17 06:32:37 · 1 answers · asked by Anonymous

A bar of lead (bar A) is in thermal contact with a bar of silver (bar B) of the same length and area (Fig. P11.59). One end of the compound bar is maintained at Th = 86.0°C while the opposite end is at 30.0°C. Find the temperature at the junction when the energy flow reaches a steady state.
________°C
http://www.webassign.net/sercp/p11-59alt.gif

2007-05-17 06:24:34 · 2 answers · asked by Emma 1

2007-05-17 06:06:38 · 2 answers · asked by Anonymous

Microwave ovens heat food by sending short waves through food to excite the atoms and make the food hot. Would it then be possible to send long waves through things like food and water to "slow down" the atoms and thus cool them? Would these be called "macrowaves"?

2007-05-17 05:01:53 · 5 answers · asked by norbert 1

http://www.adimoga.com/ce-este-in-jurul-nostru/

2007-05-17 04:19:23 · 2 answers · asked by brlmnd 1

My botany lecturers assured me that darkness was not simply the absence of light, but a type of light. True or false?

2007-05-17 03:25:42 · 16 answers · asked by Anonymous

A person whose eyes are 1.85 m above the floor stands in front of a plane mirror. The top of her head is 0.11 m above her eyes.

a) What is the height of the shortest mirror in which she can see her entire image?

b) How far above the floor should the bottom edge of the mirror be placed?

2007-05-17 02:47:08 · 2 answers · asked by Alan l 1

2007-05-17 02:34:39 · 2 answers · asked by helene 1

I don't mean by covering up light, but by emmitting something that takes away light.

2007-05-17 01:41:31 · 13 answers · asked by Dylan 3

. If the radius of the earth, assumed to be a perfect sphere, suddenly shrinks to half
its present value, the mass of the Earth remaining unchanged, what will be the
duration of one day?

2007-05-17 01:15:29 · 8 answers · asked by hafsa a 1

. A car goes along a section of road shaped like the letter S. The speed of the car stays constant. Discuss how the acceleration changes, and make a rough plot.

2007-05-17 01:10:09 · 7 answers · asked by hafsa a 1

2007-05-17 00:58:35 · 5 answers · asked by Timbo 3

Does anyone knows which factors determine type of power plants used and newly built?

2007-05-17 00:30:56 · 2 answers · asked by Anonymous

how do helium baloons float? or any gas lighter than air. if a baloon filled with air gets pulled to the ground due to gravity (weight of baloon etc.) why do helium ones get pulled away from the earth. they must have an opposing force stronger than gravity +the weight of baloon. also hypothetically what would happen a helium baloon in a place with little to no force of gravity? in space would they just shrink or explode?

2007-05-17 00:29:02 · 14 answers · asked by Anonymous

I heard it was a group of scientists. Who were the people that started quantum physics and how did they do this?

2007-05-16 22:57:12 · 6 answers · asked by worried person 1

2007-05-16 22:32:20 · 2 answers · asked by Anonymous

I always go cross eyed when i think of space as infinite, but if it isnt and it is contained, what is it contained by and what exists outside the container?

2007-05-16 21:43:20 · 8 answers · asked by Anonymous

Do electrons contribute to global warming?

2007-05-16 21:12:46 · 3 answers · asked by Anonymous

2007-05-16 18:43:50 · 4 answers · asked by Candice M 1

A woman is standing in the ocean, and she notices that after a wave crest passes, five more crests pass in a time of 52.0 s. The distance between two consecutive crests is 28 m.

period:
frequency: Hz
wavelength: m
speed m/s

2007-05-16 18:07:45 · 4 answers · asked by Alan l 1

2007-05-16 18:06:46 · 7 answers · asked by Anonymous

2007-05-16 17:46:35 · 2 answers · asked by afcrewchief2002 2

this is a picture of the diagram.

http://img.photobucket.com/albums/v421/clarinet_xy/picture.jpg

2007-05-16 17:33:34 · 1 answers · asked by twinkled1990 2

2007-05-16 15:55:04 · 3 answers · asked by Anonymous