Classical Physics

I just finished learning about vector components in my class, and I was hoping to understand the vector notation i hat, j hat, and k hat, but our book doesn't use that notation and gives an unsatisfying description of what the bold units stand for. Can someone please give me an overview of what they mean, and why they are without units? Thanks...

If Earth were hollowed out only to it's outer layer of crust, what would happen? Would the Gravity decrease? Would the Gravity, if it remained, would it implode into itself? or just break apart into space? I'm in middle school, so a simple answer would be helpful. In the words of Friedrich Nietzsche, "The"

We all know that 100% cannot be transferred from one system to another. However, what if different forms of energy can efficiently transfer more energy than others? For example: Can kinetic energy transfer more energy than chemical energy? Can Thermal energy transfer more than mechanical energy? Can electric energy transfer more efficently than magnetic energy etc. -Or is energy nondiscriminatory in all its forms, and transfers the same regardless of what form it is in?

Hello everyone, First time poster here. My question is..."When using a magnet to levitate a object (Magnetic levitation) what is the downward force on the bottom magnet? Example: If I had a 1kg magnet and was able to push it vertically using another magnet, and it didn't slide off, what would the downward force be? half of the weight being lifted + gravity?

Hello . Have a question and am interested to find a simple equation to include mass as a variable regarding stopping distances of a car In the UK highway code..... a braking distance = 14m for a car at 30 mph (48 kph) my questions are..... if you load the car up fully (increase mass)..... then (for same v) that distance will increase???? Q1: by how much ? Q2: what's a simple equation ? NB 1. [The car and the road conditions are the same for each stop] 2. [the original car is say 1000kg] 3. [the fully loaded car is say 1500kg] thanks for time / thoughts inq

Tell me where I go wrong in this, pls. 1. gravity is related directly to the magnitude of the relevant masses and inversely to the distances squared, NOT the density of the masses. 2. A large star, of mass m, and distribution of mass radius r1 starts to cool, and eventually collapses into itself to form a super-dense material-still of mass m, but now of a smaller radius of distribution of mass r2. [Laws of Conservation] Q. How can gravity of the collapsed star change to attract other objects into its black hole, unless it didn't because it was a pre-existing property of the gravitational field? 3. The gravity field strength of the collapsed star is no…

Is there a change in frequency of sound for an observer at the center of a circle for a sound source moving in the circle?

Hi all, Now im no expert in this field, However i came across this after seeing a program on the television and it showed this "craft" or device working. And it really is remarkable. It's basically a device that floats upwards with only bare materials. I think the man's name was tim ventura. Now if you search for "tim ventura's Invention" You will get some pretty interesting results. here is a link to the main thing. http://www.infinite-energy.com/iemagazine/issue45/thelifterphen.html And also could this be related but of course a good few hundred years or some fairly extensive research down the line maybe? http://www.ufos-aliens.co.uk/plasmaufo.htm (please dont star…

How to Understand Classical Physics?

I couldn't solve this problem. Could anybody help me with a solution process that I can comprehend your thinking. Thank you.

In reference to the average change in kinetic energy over time for waves moving along a string, (1/2)*u*v*(w^2)*(ymax^2)(average of ((cos(kx-wt))^2) over time), my textbook says "the average value of the square of a cosine function over an integer number of periods is (1/2)", thus the above equation reduces to (1/4)*u*v*(w^2)*(ymax^2). Can anyone explain the cosine identity, or whatever it is, used here(the other variables are not important, I only have question about the identity in the quotations)? Also, what is the difference between the speed of waves defined as v = (wavelength)*(frequency) and v= square root of (tension/linear density)? My book says the speed is …

hey, my teacher says that centripetal force is the real force and centrifugal force doesn't really exist. whereas my philosophy is quite the opposite. we argue that an object travelling in a circle experiences an acceleration towards the center of the circle. but i find it hard to wrap my head around that concept. if you were on the curved ramp of a highway entrance, you don't feel that centripetal force, you feel that centrifugal force, you being pulled out and away from the circle. the earth spinning in a circle doesn't increase the gravity we feel pulling on us, it decreases it. we experience acceleration away from the center, aka the centrifugal acceleration. so w…

I have got more and more confused since the question dawned upon me that "Is there anything like what we call time?". Is it relative to mass, tangible? Is there any way it can travel in a different direction? Whoever has some authority in this subject, please answer these questions, or any one of these. Although I do not know if present-day science can do so to a satisfactory degree.

In the proofs of the inverse square law for planetary orbits, as deduced by Newton in the Principia from Keplers Laws, he assumes lots of properties of the conics. Mathematicians in his day were well versed in Geometry, including the Conics. Not so nowadays. I started with Apollonius but found it tough going - many proofs are very long. Archimedes showed that an ellipse is also a section of a right cylinder, and this simplifies some theorems. Then again, Dandelin spheres are great for proving other properties. I found two other proofs myself, much easier than Apollonius, in the case of the parabola. If anyone else would like to be able to follow Newton's geom…

Hello, I'm new here. Yesterday I was on my bed taking some photographs of the lamp on the ceiling, with my Motorola EX130 mobile phone. The strange thing I noticed was that bringing the mobile in a certain inclination and position, before taking the photo, I could see all the colors of the visible spectrum around the fuzzy white halo which I'd already seen every time. In fact, now that I took the photo, the effect always arises again when I rotate my mobile by about 45°. Now I'm asking me, who haven't already studied optics (but I'm going to start next month): why did the different parts of the visible spectrum place themselves around the white halo of the la…

What is the biggest gravitational force in the Universe??

The Doppler Effect is accounting for relative movements of source and observer at constant velocity meaning changes in frequency are sudden but remain constant. Now can we also have source and observer moving at accellarations and frequencies changing at certain rates?

I have a question about a velocity selector. If one shoots a positive particle like a H+ cation through the selector, how can one force the particle to go more toward either the positive or negative plate? In general, one wants for the magnetic and electric fields to be equal and opposite and thus the particle can move straight. However one can alter either the magnetic or electric fields to force the particle toward a particular pole, correct? Once can also increase the velocity of the particle. If the velocity is increased, then B would decrease and so the particle's direction would be dictated by the Electric Field, correct?

1+1-1+1 = mc2 if 1 =mc^2 / 2 + o=mc^2 patty its zero

btw think of this. we live in our solar system what is pretty young and other systems are old because how long has light taken to travel from them to here. but if u would stand on other system it would be same thing backwardsa adn then think of this does light have a age itself like c + age of c i dont mean just how fast light travels that way i mean does this symbol has age itself c ??? c is how speed of light in years i mean age of c

Here's a start, any object falling from the sky has its weight multiplied due to the gravitational push towards earth. So for instance if the arrow was shot into the air and landed - it would have landed at the gravitational push of about 32.2 ft per second (or 9.8 m/s) for each second that the arrow falls until it reaches its terminal velocity. For e.g. the arrow is going down in 10 seconds, 9.8 x 10 = 98. So the arrow hits at a speed of 98 m/s. In short = The higher the arrow is shot into the air the more faster it is going down. So going back to your kevlar being strong enough to withstand arrows - it won't stand a chance as the arrow is going down at a fast speed (you…

What happens to the magnetic field when the helix of a solenoid is, itself, bent into a larger helix shape?

I am sure you have seen the flashlights that you shake to charge. I know they function by building a charge off of a magnet moving through a magnetic coil. I was wondering what the formula for the amount of electricity generated by this for every up and down (as one unit)? Also, what is a good ball park on force it takes to pass the magnet through the coil and what is an easy/typical base variable(s) to start from? (such as, # of coils = 100 vs 57)

Hello everyone! I am having a bit of a problem understanding a paper. Usually the authors use the electroluminescent spectrum to describe an emitter, but in this paper the radiant power is constantly cited. What is the relation of these two? Usually the EL spectrum is a.u. vs wavelength and radiant power is (in this paper!) W/(sr m^2) (usually called radiance). Can these two quantities be converted (as the time information is not known)? best regards, Chris

hello have found this interesting question (interesting to me).... along with an equation that is supposed to allow the answer..... but I plug in the data and never get the same result as is correct. could someone set it out with the data so it flows to give -690N (if correct).... thanks (not an exam question or anything.... I found it and would like it as a model to find average brake force.... cheers) A 1100-kg car traveling at 27 m/s starts to decelerate and comes to a complete stop in 578.0 m. What is the average braking force acting on the car? answer: (a) -690 N (b) -340 N © -410 N (d) -550 N the answer is said to be (a) -690N and the suggested eq…