Physics - August 2007

A car traveling with velocity v is decelerated by a constant acceleration of magnitude a. It travels a distance d before coming to rest. If its initial velocity were doubled, the distance required to stop would? A) quadruple B) Stay the same C) double as well D) decrease by a factor of two please explain why also

2007-08-11 18:09:56 · 5 answers · asked by Anonymous

After a nuclear explosion, how long will the area affected be radiated?

If people hide in a nuclear fallout/shellout, how long before a human could safely venture to the outside world?

2007-08-11 16:55:04 · 10 answers · asked by Anonymous

The barrier potential of the PN junction diode is caused due to migration of charges across the junction. This potential is due to the differential charge density, across the junction .If the cross section area of the junction is increased, the number of charge carriers is increased and the barrier potential must increase.But practically(even theoretically) its not possible to get more than 0.6V. Why this is so ?

2007-08-11 16:33:10 · 2 answers · asked by Chander's 1

C: Celsius
1 How much heat is needed to raise the temp. of 90kg of water from 18c to 80c?
2 if a 1MJ of heat is transferred to 10kg of water initially at 15c what will its final temp be?
3 if 12kg of water cools from 100c down to room temp. (20c) how much heat will it release to the environment?
4. how much heat would be needed to warm 1.6kg of ice from -15c to its melting point of 0?
5. A 5kg lock of lead at 250c cools down to 20c. How much heat does it give off in doing so?
6. if you must do 500J of work to operate a pulley system, and the pulley system lifts a 50N load to a height of 3m, how efficient is the pulley system?
7. For every megajoule of chemical potential energy in the fuel used to run a certain truck only 120kJ of useful work is done by the truck in making itself move. How efficient is the truck? Where are some of the places that the energy from the fuel is wasted?

2007-08-11 16:24:12 · 2 answers · asked by Anonymous

hooked like a group of resistors except instead of a resitor holding the parallel position furthest from the terminal, a simple length of copper was in its place, completing a resistance free loop between the terminals for electricity to travle. Will less electricity travel through the resistors now as a result? Will no electricity travel?

e.g.


(+)(-)___
l^^^^^^^^l
l^^^^^^^^l
l^^^^^^^^l
l^^^^^^^^l
l______l

2007-08-11 16:19:55 · 6 answers · asked by kmm4864990 1

2007-08-11 16:00:41 · 8 answers · asked by Anonymous

If I had a DC brushless fan that requires 12vdc to operate, and realized this fan can produce electicity. Would it be possible to make an array of the same type of fan and let wind blowing on the array, power the lone fan for cooling? Is this possible?

2007-08-11 15:59:08 · 3 answers · asked by smittybo20 6

The first is how many nuclear bombs are on the planet right now, i hear it was 60,000 but i'm not sure,the second if you add all the nuclear bombs up to one singer bomb how many megatons would it be.

2007-08-11 15:03:00 · 1 answers · asked by carlos sims 2

Coasting from rest down a certain hill, whose slope is variable, I reach a speed of 18.02 m/s at the bottom. If I coast from rest down the second half of the hill I reach a speed of 15 m/s. Ignoring the effects of air resistance and friction:

How fast would I therefore be going if I coasted from rest down the first half of the hill?
How high would I have to climb from the halfway point reach the top?

2007-08-11 15:01:11 · 2 answers · asked by benzene boy 1

You have been hired to check the technical correctness of an upcoming TV mystery, "Mari Mar in Space". The mystery takes place in the space shuttle. In one scene, the astronaut Mari Mar’s safety line is sabotaged while she is on a space walk, so she is no longer connected to the space shuttle. She checks and finds that her thruster pack has also been damaged and no longer works. She is 200 meters from the shuttle and moving with it. That is, she is not moving with respect to the shuttle. There she is drifting in space with only 4 minutes of air remaining. To get back to the shuttle, she decides to unstrap her 10-kg tool kit and throw it away with all her strength, so that it has speed of 8 m/s. In the script, she survives, but is this correct? Her mass, including space suit, is 80 kg.

Pls show all necessary calculations with explanations pls, best answers gets 10 points...

2007-08-11 14:49:37 · 2 answers · asked by Sammy Baby 1

You have been hired to check the technical correctness of an upcoming TV mystery, Mari Mar in Space. The mystery takes place in the space shuttle. In one scene, the astronaut Mari Mar’s safety line is sabotaged while she is on a space walk, so she is no longer connected to the space shuttle. She checks and finds that her thruster pack has also been damaged and no longer works. She is 200 meters from the shuttle and moving with it. That is, she is not moving with respect to the shuttle. There she is drifting in space with only 4 minutes of air remaining. To get back to the shuttle, she decides to unstrap her 10-kg tool kit and throw it away with all her strength, so that it has speed of 8 m/s. In the script, she survives, but is this correct? Her mass, including space suit, is 80 kg.

Pls show all necessary calculations with explanations pls, best answers gets 10 points...

2007-08-11 14:49:10 · 1 answers · asked by Sammy Baby 1

Why is it that on high voltage electrical equipment, the blobs of solder should be rounded and smooth??

2007-08-11 14:44:39 · 2 answers · asked by sdjfhdkjsfgkuae 2

What will be the tension in the string holding a ball which is being swung in a circle of raidus .7 m if the ball is going 2.5 rev/s. Assuming the sytem is in free fall?

What is the tension if the system was on a sationary with respect to surface of earth, w/the ball being swung in a vertical circle, when the ball is at the top of its arc.

What if the ball is at the bottom of the arc?
What if the ball is at 1/2 height?

2007-08-11 14:33:21 · 3 answers · asked by e=mc^2 1

I know that matter emits and absorbs radiation, as shown by the standard model in detail. However, I am taught that matter itself acts as a wave, different waves corresponding to different particles. Is there a 'matter spectrum' all it's own or can it be considered an extension of the electromagnetic spectrum? (and if so, where on the map is it?)

2007-08-11 13:57:11 · 6 answers · asked by Rose P 1

2007-08-11 13:47:26 · 2 answers · asked by toolmaker 1

Why is it that the amount of smoke leaving a factory can be reduced by placing a charged object inside the chimney?

2007-08-11 13:22:59 · 2 answers · asked by sdjfhdkjsfgkuae 2

2007-08-11 13:19:03 · 3 answers · asked by toolmaker 1

A girl throws a ball from a window to her sister in a window 4 meters above. Her sister catches it 1.5 seconds later. What was the initial velocity and what was the velocity just before the ball was caught?

2007-08-11 13:16:23 · 3 answers · asked by refdxf 2

I have a theory that matter and energy are at two opposite ends of a continuum and that accelerating matter changes it into energy while matter, when slowed down sufficiently, assuming it is possible, will become matter.

2007-08-11 13:00:34 · 6 answers · asked by Danman 1

http://www.collegehumor.com/picture:1754808

It says it makes it easier to drink out of, but I don't understand why they have so much extra tubing. Can someone explain this to me?

2007-08-11 12:20:57 · 3 answers · asked by Anonymous

For example matter+anti-matter, or matter+/-energy spontaneously produced out of nothing. If this is possible, can it be one possible theory for the beginning of our universe?

2007-08-11 11:29:53 · 6 answers · asked by Stamatios D 5

What is, in simple terms, supergravity?

Can I have equation(s) for this type of gravity?

2007-08-11 11:06:11 · 1 answers · asked by Anonymous

In simple words, can someone explain the difference between gravity and paragravity?

Also, can I have equations for both?

2007-08-11 11:04:41 · 2 answers · asked by Anonymous

2007-08-11 10:02:47 · 25 answers · asked by John S2005 3

what can you conclude about wave speed in shallow versus deep water?

2007-08-11 08:30:18 · 2 answers · asked by Anonymous

you are in a row boat on a lake and a speed boat passes you. your boat starts to bob up and down. you observe that you bob every .5 seconds, and the waves are 3.0m apart what is the wave speed?

2007-08-11 08:27:57 · 5 answers · asked by Anonymous

Lets say I have a 6” metal ring with a free wheeling ball bearing (bb) (1” in diameter, about 0.03kg) in it and a 3” rotor arm attached to a motor at the center of the ring. As the rotor spins it pushes the bb around and the cf forces pushes the bb to the wall of the ring. I rotate the arm at “100” rpm, bb goes around at 100 rpm.

the bb exerts a cf force on the inner face of the ring by running over it. however, is see no cp force acting on this system. The rotor arm pushes the bb around – therefore, always pushing a constant weight of 0.03kg around - however, with increased rpm the bb produces an increased cf force against the ring but there is still no cp force present or acting on the bb? Am I missing something with the rotor arm?

2007-08-11 07:58:51 · 1 answers · asked by Willy 1

What exactly does that mean to you? Anybody with a degree is physics or quantum physics, think they could kind of break this down for me?

2007-08-11 07:52:55 · 6 answers · asked by lovebug512 3

Does the passangers feel the explosion before being blown apart..like when the plane hits the ground at full force and it explodes, Does the passangers even know whats going on?? My aunt died in AeroMexico flight 498 and I was curious if she felt the explosion or not....

2007-08-11 06:57:29 · 3 answers · asked by Anonymous

2007-08-11 06:30:13 · 2 answers · asked by Aftab Banoori 2