Physics

I was discussing lightbulbs the other day, and suddenly we realized that we don't know what resistance is. I know the V = I*R laws and other basics. I know that the wire in a lightbulb glows bright because all energy of electrons is lost in the wire because it is thin and therefore has a (relatively) high resistance. Let's look at a DC current in a wire (or any other resistor, they all just heat up to dissipate the energy). So, these electrons entering the wire lose their energy somehow. I'm visualizing it as high energy electrons in the valence band getting too close to another electron in the valance band, pushing the next one forward. That one in turn pus…

So, I'm sure we've all seen plenty of movies where, in order to escape some enemy, Our Intrepid Hero jumps off something really tall into water below. I also recall hearing the urban legend that hitting the water from more than 90 feet up is like hitting concrete. This is obviously wrong, since the world record high dive is almost twice that (172 feet, Dana Kunze). So, what is the actual maximum height, and if nobody knows, how would it be best to calculate it, based on force, energy change, or impulse? Mokele

In physics class today, my teacher told us that we will have a project where we have to make an egg launcher with an uncooked egg. Our mission is to launch the egg 2 feet away into a cup (With the correct amount of force). Bonus: If the egg didn't break, we'll get a perfect score, and don't have to pass in our lab report. If it does break, then we'll have to pass it in. I'll get more information tomorrow, with the details. Any suggestions how I can make an egg launcher that won't break the egg when it lands in the cup?

okayy well i think i have an answer..but i dont know scientific reasoning.. heres the problem: Consider drops of water that leak from a dripping faucet. As the drops fall they a)get closer b)remain at a relatively fixed distance from the other c)get further apart i said "c"..but now i need scientific reasoning.. how do you put scientific reasoning to that??

Just note I couldn't find this on Google. So why? Why not slower, or faster? This is a confusing question that I hope someone could answer. And another question along these lines, if a photon has no mass, how does it "fall" into a black hole. Gravity is the force of attraction between two objects, right?

Im not too sure how to word this so hang with me Well, my year. 8 science teacher is not the brightest bulb in the box, but he absouloutly stumped me with a question today; "Why is gravity there?". Is there even an answer for this? If I dont get a good answer by monday I have a lunch time clean up (long story). Am I crazy or is that an impossible task to set (especially for an 8th grader).

Can someone please tell me how a glockenspiel works and the physics behind it :/ Please I really need help

Why is there something rather than nothing? I know that matter and energy are interchangeable (one can be converted into the other) but can matter and energy come from nothing? Did the universe come from nothing or is there something which is eternal (has no beginning and no end) and this eternal thing is the cause of everything?

Interesting article in New Scientist (Australian printed edition 5 April page 36) by Prof. Michio Kaku - theoretical physics at City University of New York - and author of "Physics of the Impossible." He discusses what scientific and technological developments might occur in the future - which will happen soon, or later, and which are plain impossible. He points out that the history of science is full of luminaries that make lousy predictions. Examples are Lord Kelvin denying that heavier than air flight is possible, claiming that X-rays are a hoax, and that radio has no future. Ernest Rutherford denying that the A bomb will ever be possible. Prof. Kaku s…

We know that there are lot of new inventions in physics so why are we still learning the old thing not mesons and quacks?

Alright, so today in my science class we attempted to measure the weight of my teacher's 2006 Honda Civic. He claimed that by calculating the surface area of each of the tires, and the PSI in each of the tires, we could find the weight of his car. We used the formula P (Pressure)=F (Force)/A (Area) rearranged for this lab: F=PA Because we only had tire gauges that measured PSI and not Pa, we went with standard units (Inches for length/width, PSI for pressure, lbs for weight). The weight came out to be around 4000lbs, obviously WAY too high for a Honda Civic. The posted weight was 2628lbs. However, the measurements we got could NEVER have worked out because t…

Is there any difference in the term 'White' and 'Colourless' in Optics? Is a light ray colourless or white. In many books colourless and white means one and the same. But white is the colour of milk while water is colourless.

It is known that when a gas expands it cools down. But why does the decrease in pressure cause the molecules of the gas to slow down?

It's said that Rotation is when an [rigid] object turns about an internal axis e.g. a merry-go-round or gramophone record whereas Revolution is when an object turns about an external axis e.g. the Earth around the Sun. So why are gramophone record speeds given in terms of Revolutions Per Minute (RPM) and not Rotations Per Minute because the whole of the record is rotating about an internal axis?

Some countless websites on Google claim that there is life beyond death but what does science have to say about this especially biology, chemistry and physics? Is life after death just wishful thinking or is there some science beyond this? If evolution is indeed true and humanity indeed evolved from more fundamental forms of life, does this mean that there is no life after death?

So I want to measure the distance between two objects wirelessly, which should preferably give out the same type of waves to do so. My prediction is that slower the speed of the wave, more accurate we can measure the distance between the transmitting objects. So radio waves or sound waves are much slower than Bluetooth which works at the speed of light? if I'm correct. I'm a complete novice to every form of science, especially physics. So please tell me the most accurate and the most energy efficient way of calculating the distance between two variable objects wirelessly. It does not have to consist of a method of waves. Thank you, Waiting in anticipatio…

We just learned what these are today in math. I get the concept of it, but im not sure of its application. Lets say you have a equation with a negative inside a square root. You turn it into an i. Im not sure how this would help you. I havn't taken calculas yet so maybe i'll learn it then?

http://www.foxnews.com/world/2012/05/27/german-teen-solves-300-year-old-mathematical-riddle-posed-by-sir-isaac-newton/ Does anyone know what is this problem that was unsolved for 300 years, and the other part about 'bouncing' problem?

Ants do not die when they fall from a very high place. But on the other hand humans will collapse when they fall from a very high place. Can you give a better explanation place, please..

Do the electric impulses in the body travel at the speed of light? For example, if something brushes your toe, or your eye detects a flying mosquito, does it sent the info to our brain at the speed of light? I'm not asking how fast the brain processes the info, just how quickly it's reached by the signals.

Logically, I equate resistance with a frictional force inherent in a conductor. So, I would expect that resistance should be a vector quantity, antiparallel to the direction of the current. I liken this to the the frictional forces acting antiparallel to a force that pushes an object across a floor. However, my professor tells me that resistance is a scalar quantity. Why is this?

Does the cardboard material used in boxes protect from light and UV? I keep objects sensitive to light and UV inside these boxes example: DVD discs and plastics

Is it true that if you throw a ball west, with the same power as a ball east, that it will travel further? If so what % distance difference would there be? Does a ball thrown in a straight line north or south actually curve. What's the mathematical function of that line? Would it be variable by altitude and lattitude due to increasing circumference of the rotational circle? How would throwing a ball in an arc or parabola compare to thrown as straight as possible? How does this apply to aviation? How does it affect ballistics. Are nukes programmed to compensate? What about artillery, is the ranging different? If you throw a ball straight up and…

I assume light have no mass also gravitational force only works with mass and light can be pulled by gravity field. Those 3 things can be mentioned in scientific documents. But i see there is a contradiction .Or is there anything i know wrong? How can i solve this paradox?