Classical Physics

If a Stirling engine recovers energy from the exhaust gases(they have an high temperature) of an Otto engine then the total(Otto-Stirling) efficiency can be very good, I think it can be more high than a single Stirling engine. Are you convinced?

how was G calculated? on a side note: i know it wasn't anywhere close to what i did, because i used the inverse-square law for gravity in a thought experiment. i didn't just solve for G, so i may have messed up in getting the equation. the experiment is: you are on a rocket on a planet. you fire your rockets and leave the planet(forgetting the fact that they use curved trajectories and orbit. no, forget that. it goes straight enough in the beginning.). use you initial speed, final speed, acceleration, mass of planet, and gravitational acceleration of the planet to find G. [math]F=ma[/math] [math]{V_f}^2={V_i}^2+2a{x}[/math] [math]F=\frac{G{m^1}{m^2}}{r^2}[/ma…

Recently was asked to make a presentation on some math involved in a movie. I chose the Men In Black. The scene I selected was the part where the 2 are in the Queens tunnel and they go on the ceiling of the tunnel and continue to go at an unusual high speed on the ceiling and eventually get down and out. I would just like some insight on what kind of math I should present and how to present it. Also some basic "if it were" kind of questions. Thanks for any help.

Just a little question that has been bugging me, lets say we have a rod, and we have some kind of thrust on one end of it perpendicular to the rod, it will spin about its center of mass right? Having another source of thrust on the other side will make it rotate faster but only one will still get it to rotate...I think. Because 1 side is accelerating and the other is not, or am I really confused here.

sitting in my shed, in front of the Heater with the door closed listening to the radio, I noticed a shaft of light coming through the hole in my door (I use it keep an eye on the main gate). this shaft of light was like a laser as my cig smoke passed through it, the spot on the opposite wall wasn`t really much bigger than the hole in the door, I examined it, the total distance was 1.75 metres from the spot to the hole. I noticed that Around the spot I could see movement? I looked through the hole and the only thing moving was clouds and a few birds. I blew smoke at the spot and was astonished to find that it wasn`t a spot at all but very faintly it had perfect imag…

Hi I was wondering how big/small would an asteroid have to be to generated about an equal devestating effect as the earthquake (8.9) if it woud impact at the same place. The earthquake energy is about 48 million tons of TNT (if I'm correct) (assuming 6 million tons of TNT= 8 on the Richter scale) So it are actualy two questions: - size of an incoming asteroid based on this link that would be less than 75meters http://www.astronomycafe.net/qadir/q975.html - how to calulate the energy contained in a wave of water? correction: Richter scale isn't a factor 10 but 10^1.5 so the energy would be more likely about 1412000TJ or 3374 Megatons. also Richt…

Why does rotation of a body create gravity(like in space, I mean)?

This is my first time posting here, hi to all and thanks in advance for any replies. I took highschool AP physics, and have read a little bit of new stuff like The elegant Universe, so I consider myself to have a basic uderstanding of physics. My question is about earth orbits. I know the equation for a projectile orbiting the earth is a parabolic one (I hope I am correct here, otherwise my post is unecessary.) Now in newtonian mechanics, if you fire lets say a cannonball fast enough, it will not strike the earth but will orbit it in a circle. I am confused as to how the equation for a projectile can be parabolic, yet an earth orbit can be circular, isn't a …

Probably a stupid question...Say a person were on a platform freefalling toward the ground at a high speed. If, at the exact instant before impact, that person were to either push directly opposite the downward force (jumping up) or leapt sideways, would it kill enough speed to keep them alive?

My teacher said that a box 1kg leave up by a man 50m, then he just said the potential energy= work done , so PE=500 J. The explanation may be a bit vague that cause me think of the work done is by human efforts against the gravitational force. Contradiction arises as F by human not = mg, otherwise, no movement or continuous movement. Here is my illustration. I think that after a certain distance rose, if it is released, the earth pull F=mg , this is the source of the work done. And where have the human efforts gone? Some stored in object as PE, where are the others, KE? and 1.Potential energy is defined as the work done by gravity, right? 2.Energy gain refers t…

Could anyone help me with this problem? a force of 40.0N accelerates a 5.0kg block at 6.0m/s^2 along a horizontal surface. How large is the frictional force? What is the coefficient of friction? I can't figure out how to get the force of friction without given the proportionality constant.

http://www.space.com/businesstechnology/technology/space_elevator_030917.html Nasa is really thinking of building one. When will it be build ?: I was just thinking won't they have a lightning problem ??? What about the static differences in the air, where is the current going to go? found the answer: "what about lightning? The tether would need a pretty thick ground wire to avoid being vaporized during a lightning strike. I guess a ground wire might only need to go up to abot 40,000 feet or so. I assume there wouldn't be a problem with lightning once above cloud level. Maybe have helium balloons at lower altitudes where lightning is a possibility a…

"I'm looking for a way to calculate the optimum angle of attack for the blade of a monocopter. It seems there has to be a stall speed and hover speed, somewhere in between is the optimum. Firstly, if there are any RC folks out there, I'm guessing there is a formula which will give a lift number to a laminar flow airfoil. This number would probably have to have adjustment based on wing length versus width (as an airfoil can have a similar square area, though one could be twice as long and as thin as another). Secondly, all the factors would have to be involved which include (and I may leave something out) Dry weight Loaded weight Cd (probably a constant for t…

1. (Yikes I hope I posted in the right forum... Ah well. Here goes.) How do I determine the composition of an alloy (of, say, two metals) from its specific heat capacity? Can I do something like... c1*m1*dT + c2*m2*dT = c3*(m1 + m2)*dT Where c1, c2 and c3 are specific heat capacities (c1 and c2 for the two metals the alloy is composed of, and c3 for the entire alloy) m1 and m2 are the masses of each of the two composing metals contained in the alloy and dT is the change in temperature. (But dT wouldn't really matter would it...) 2. In order to determine the power an escalator exerts... Say I know how much the system masses (let's call this m, for m…

Lets say you throw a ball in the air, the instant the ball leaves your hand the force you applied to the ball no longer affects it, rather it's Newton's laws, that it tends to stay in motion. The four other forces in nature cause it to slow down. Here's my question. Isn't the throwing of the ball be an kinetic energy transfer from you into the ball? Whouldn't the energy from you throwing the ball still affect it's motion? So even if the force you applied doesn't affect the ball, wouldn't your energy?

Not sure if this is where this post should be but here goes. I need to calculate the minimum thickness required for a welded steel pipe of material SA 312 grade TP 347, plain end. The outside diameter of the pipe is 273.1 mm and the operating pressure and temperature are 2000 kPa and 400 degrees C respectively. I believe i need a table from the ASME Poer Boilers Code but the only thing i could find was a reference in Paragraph PG.-27.2.2 and no table.Anyone have any ideas? Thanks

Is there a formula to work out the speed in this situation? A 65kg man jumps off a 2m high wall, could I find the speed from this (by time he hits the ground)? Thanks!

The demonstration is supposed to show that the equilibrant is equal and opposite to the resultant of 2 forces. My teacher suggested to nail some nails equidistantly around a circle on a wooden board. Then hook 2 force gauges onto 2 nails and a key ring in the center of the circle. Then hook a 3rd force gauge onto another nail and the key ring. Then measure angles and look at the force gauge to use a vector diagram to show that the key ring will be in equilibrium if and only if the 3rd force is equal and opposite to the sum of the first two. Does it seem sound in theory?

According to Newton's third law, v t p u o u o It is a rope with a wheel,v. If 50N is applied from u pulling towards the ground, what's the reaction force? From o to p ?

Okay so I've been trying to find units for physical formulas which would negate (as many as possible) constants from the equations as possible. (Is this even possible, heck I don't know, I'm just bored.) Like instead of F = G*mM/R^2 it would be F = mM/R^2 That means that the unit for mass and lenght would be defined so that [m]*[m]/[L]^2 = G But I need to find multiple equations in order to solve this. I've done some calculations but with no luck. I'm having trouble finding usable equations. Thus far I've used the above, F = k*qQ/R^2 and E = hf. I've also tried to attack the universal gas constant and the permittability of free space, but I get no…

I want to question about what's vector linear mean? Why is temperature measured in a thermometer is a scalar measure?

Imagine there is an object on the surface. The surface is uniform smooth(with same friction over the all surface and friction is greater than 0). Let's define the friction be f. Act a f force to horizontally to the object continuously, it is continuous added. It is obviously stationary. I'm quite confused of here then. If there is 1N force pushed to it in the same direction to the f force added by hand. What will be observed? a.Move with acceleration first, then remains the velocity later on. b.1.If f>kinetic friction, then the object accelerates first then decelerates to stop. b.2. If f> kinetic friction, then the object will accelerates continuously forwa…

A boy can walk up a stationary escalator in 90s. Standing on the escalator when it is moving, the student goes up in 60s. How long would it take the student to walk up the moving escalator? the problem sounds easy, but its not.... atleast not for me. so any help in solving would be greatly appreciated. thanks! -mak10

In a particular well-known experiment known as Newton's ring interference pattern, we get a dark fringe at the point of contact of the glass lens and the plane glass surface, followed by rings of bright fringes and dark fringes. This seems to show that at that point of contact, the monochromatic light reflected from the glass surface is 180 degrees out of phase with the light reflected from the lens surface. How can that be possible?

I've been reading a paper by someone who thinks gravity violates the law of conservation of energy, and I can't quite find the flaw in his reasoning. He says that because the pulling force of gravity never ceases and that it doesn't seem to get the energy to apply this pulling force from anywhere external to itself, it represents a source of contiuously generated energy that comes out of nothing. It would be analogous to someone spinning a rock tied to a string around in circles forever without ever consuming energy in anyway in order to keep up the energy required to spin this rock. I've often wondered about this myself. When I took physics in my first year at univer…