Laws Definition and 1000 Threads

I have to write a paper about the derivation of Kepler's laws, but I don't understand how the derivations work. If anyone could help explain to me how they work.

Homework Statement [PLAIN]http://img203.imageshack.us/img203/5679/physics2h.png Homework Equations Included above I believe... The Attempt at a Solution a) i think dq=\lambda2\pidy Some of the calculus that we are using I am shaky on and I just don't understand what is being asked here...

What's the difference between a physical Law and a physical theory? thanks

Homework Statement An 80 kg spacewalking astronaut pushes off a 640 kg satellite, exerting a 100 N force for the 0.50s it takes him to straighten him his arms. How far apart are the astronaut and the satellite after 1.0 min? 2. The attempt at a solution F = Ma. Two different masses and two...

Homework Statement Hello, I'm trying to revise for my probability exam next week and am getting a bit hung up on how to show a sequence of random variables converges. For example, how would I got about doing this question: Let {X_{n}:n\geq1} be a sequence of random variables with...

Jack and Jill are on skateboards. Jack weighs 3 times heavier than Jill, and is pushing Jill(a horizontal force on Jill's back). Immediately after Jack let's go, what are the speeds they're moving at? (No need to take friction into consideration) F=ma Okay, I do understand that they will be...

Homework Statement 1.On an aircraft carrier, an F18 Super Hornet can be catapulted from 0 to a take-off speed of 248 km/hr. The loaded mass of this jet in fighter configuration is 21,320 kg. The length of the angled section of the flight deck on the US Nimitz class carriers is 237 m. What...

Homework Statement A 41-kg box is thrown at a speed of 235 m/s and is brought to a halt in a collision that lasts for a time of 6.8 ms. What is the magnitude of the average net force that acts on the box during the collision? Homework Equations Sum of Forces = m*a The Attempt...

Does empty space move? What are the laws that govern its motion? The big-bang set the universe expanding. But universe did not consist of matter at that time. So, what started expanding! Empty space - I suppose. But do the laws of motion govern the motion of empty space as well? Don't we need...

Homework Statement An 18kg rock is released under water. The fricitional Buyoyance add up to 129N How long will it take to fall 1.0m Homework Equations The Attempt at a Solution

Homework Statement don't mind my cruddy drawing :P R1 to R3 = 1000 Ω R4 to R5 = 2000 Ω i1 = 1mA= 1x10-3A Find the current through each resistor. Homework Equations parallel Rp = (sum)(1/Ri)-1 series Rs = (sum)(Ri)) ΔV=iRThe Attempt at a Solution i'm not sure of the best way to...

Homework Statement A 3.00-KG mass and a 10.0-KG mass are attached to opposite ends of a massless cord which is strung over a frictinoless pulley. a) What is the acceleration of the two-mass system? b) What is the tension in the cord? Homework Equations F = net forces Fg = force...

Hello, everybody! During the whole of my undergraduate study of physics, this one thing always bothered me. It concerns the interplay of conserved quantities, symmetries, Noether's theorem and initial conditions. For a system of N degrees of freedom, governed by the usual Newton's laws...

I think the non-payment of tax is a separate issue. How many people are non-taxpayers? Of more concern to me (going off topic a second) is this, care of our friends in the European Court: http://www.bbc.co.uk/news/uk-12022013

this is from chapter 4 of university physics of young and freedman q19 why can it hurt your foot more to kick a big rock than a small pebble? must the big rock hurt more? explain? but I can't see the answer at all by just applying Newtons law in the scenario of the small pebble mp is small...

Interesting article in Newscientists, thought I'd start a discussion... http://www.newscientist.com/article/dn19429-laws-of-physics-may-change-across-the-universe.html

Homework Statement http://img576.imageshack.us/img576/5773/67450733.jpg Suppose three blocks as stacked as shown on a floor which I forgot to draw and assume it is frictionless. Draw a free-body diagram for each mass Now I know my FBD is wrong because it is a misconception of Newton's third...

Homework Statement Given the following chemical reaction: Zn + HCl ----> ZnCl2 + H2(g) If you measured the total volume of collected gas over water at 20 Celsius to be 428 ml at a total pressure of 845 torr, how many milliliters of 2.6M HCl would be required to produce the correct amount of...

Homework Statement A man is pulling a wagon up a 50° up a hill. His nephew of in unknown mass sits in the wagon. After pulling the wagon 30 meters up the incline, the man slips and falls releasing the wagon. The sled, starting from rest, slides down the incline. After traveling 30 meters the...

Homework Statement A ship is in orbit 155 mi. above the earth, (a) what is its velocity? (b) How long will it take the ship to orbit the earth? Homework Equations v=(G*(m/r)).5, (2*PI*r)/T=v The Attempt at a Solution I added 155 mi to 3963 mi and got 4118 mi and that is about...

vectors were introduced because they help physicists specify laws without reference to any particular coordinate system...can we then say that position vector is really a vector because after all it depends on where we choose our origin?

Homework Statement Let f be a function let p /in R. Assume limx->p=L and L>0. Prove f(x)>L/2 The Attempt at a Solution Let f be a function let p /in R. Given that limx->pf(x)=L and L>0. Since L\neq0 Let \epsilon= |L|/2. Then given any \delta>0 and let p=0 we have |f(x)-L| = |0-L| =...

Homework Statement given initial coordinates, r(0), r'(0) and F(r,r',t) find r(t) Homework Equations r''(t) = F(r(t), r'(t), t) / m The Attempt at a Solution have no idea where to start. some hint please, seem's pretty simple but not striking me.

My final for Physics is coming up and I really, really ****ed up in this class. I don't even know how to do dot products, cross products, or let alone Newton's laws. We applied Newton's laws to some pulley problems I think. I've been going to all the lectures but it just doesn't stick -- nothing...

An artificial satellite circles the Earth in a circular orbit at a location where the acceleration due to gravity is 9.00 m/s^2. Determine the orbital period of the satellite.

Homework Statement A box of books weighing 329 N is shoved across the floor by a force of 484 N exerted downward at an angle of 32◦ below the hori- zontal. The acceleration of gravity is 9.81 m/s2 . If μk between the box and the floor is 0.57, how long does it take to move the box 3.66 m...

Homework Statement A student pushes horizontally northward on a 1.5 KG textbook initially at rest. The book is located 1.0m from the edge of a long table. the coefficient of static friction is 0.25, and the coefficient of kinect friction is 0.20. The applied force is just enough to get the...

Homework Statement So, there is a skier (the blue recktangle) preparing to do a jump. There is no friction between the skier and the jumping board, and also no friction between the jumping board and the ground. Known values are: v0 - starting speed of the skier m2 - mas of the...

Homework Statement Two forces act on a 39 kg mass to give it an acceleration of 26 m/s^2 in the positive x direction. If one of the forces acts in the negative y direction with a magnitude of 450 N, what is the magnitude of the second force. Answer in units of N. Homework Equations Fx:ma...

Hello Folks, I have attached a DC circuit consisting of two opposing batteries and 3 resistors. The first step I took was to speculate on the direction of currents in both loops. I assumed the direction of conventional current for both loops, knowing full well that the maths will tell me...

In my textbook, the proof for demorgan's law, (AintersectionB)* = A*unionB* [*=complement] starts with,saying that for all x belongs to (AintersectionB)* , x is not a member of AunionB. But how can we say that, for example, if A = {1,2,3} and B = (2,3,4,5} and U = {1,2,3,4,5}...

Homework Statement A 4.0 x 10^4kg roller coaster starts from rest at point A. Neglecting Friction, calculate its potential eneregy relative to the ground, its kinetic energy, and it's speed at points, B, C, and D. at point A : 54m B: 15m c:47m d:35mHomework Equations i got potential eneregy by...

Pls anyone can Give me full detail of Kirchoff Law of Voltage and Current pls,,,

Homework Statement A 400 N force points due Northwest. a) In what direction must a 700 N force point so that the net force points due west? b) What is the magnitude of the net force? Homework Equations No Clue.. The Attempt at a Solution Answer says its.. a) [S66`W] b) 923 N...

Homework Statement A duck has a mass of 2.30 kg. As the duck paddles, a force of 0.124 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.222 N in a direction of 50.3° south of east. When these forces begin to act, the velocity of the duck is...

Homework Statement 2 objects with mass m1=10 and m2=5 are connected by a light string that passes over a frictionless pulley, they are set up so that m1 is sitting on the desk and m2 is attached to a pulley, is over he desk. if when the system starts from rest, m2 falls 1 meter in 1.2seconds...

An object of mass 1.25 kg on a flat surface has two forces acting on it, F1 and F2 in the horizantal direction. F1 acts in the positive direction, F2 acts in the negative direction. The magnitude of F1 is 26.75 N. The object moves strictly along the horizontal x-axis, which we choose as positive...

Homework Statement 1. what happened to the amount of friction between the surface and the shoe was the force of gravity was increased? 2. when a piece of paper was placed between the shoe and the surface(table), was more force, less force, or the same force needed to pull the shoe...

Homework Statement A toboggan with a mass of 15kg is being pulled with an applied force of 45 N at an angle of 40degrees to the horizontal. What is the acclecration if the force of friction opposing the motion is 28 N?Homework Equations Is this question related to the x and y component rules...

Homework Statement A brick of mass 1.0 kg slides down an ice roof inclined at 30 degrees with respect to the horizantal. If the brick starts from rest, how fast is it moving when it reaches the edge of the roof 0.90s later? Ignore friction Homework Equations Fnet = ma v2 = v1 +...

Are the mathematical electrical laws as accurate as mechanics laws, if the input is perfect enough, or they're just good approximations?? I mean ohm's law and potential difference = electric field times length of wire (in wires), and alike laws.

Although it is commonly accepted that physical laws and values of fundamental constants are the same throughout our universe, a recent finding, in which the fine-structure constant alpha has been found to vary by a small amount (1 part in 100,000) going from one end of the universe to another...

what is wedge constant and where and how to use it?

Homework Statement Two blocks are accelerated across a horizontal frictionless surface as shown. Frictional forces keep the two blocks from sliding relative to each other, and the two move with the same acceleration. F = 1.2 N and M = 1.0 kg Homework Equations what is the horizontal...

A block can move with constant velocity even though it has an applied force. Newton's first law is NOT violated. We were going over this in class today but I don't understand it, why is Newton's first law not violated? What applied force would you need to keep the block moving with a...

A large block of mass M is going to be pulled with a constant velocity along a horizontal surface. The coefficient of friction between the surface and block is u. (1) Find the angle theta=theta_naught that the direction of pull shall make with the direction of motion for the pulling force to...

Homework Statement A block weighing 70.0 N rests on a plane inclined at 25.0° to the horizontal. A force F is applied to the object at 35.0° to the horizontal, pushing it upward on the plane. The coefficients of static and kinetic friction between the block and the plane are, respectively...

I AM NOT INTERESTED IN DIRECT ANSWERS! I'm just stuck on how to process these questions and just need a little guidance on what I'm doing wrong. I will be forever indebted and I am more interested in learning how to solve for these. Thank you! 1. A person weighing 0.9 kN rides in an...

It's a gas problem: 3 volumes N2 and 1 volume of H2 react at 344 degrees Celsius to form NH3. The equilibrium total pressure is 110 ATM and is 41.49% NH3 by volume. Find Kp assuming the gases behave ideally. So I started by assuming that I had 100L of gas. I worked the ICE table like so...

Homework Statement To move a large crate across a rough floor, you push on it with a force F at an angle of theta=21.0 degrees below the horizontal. Find the force necessary to start the crate moving, given that the mass of the crate is 32.0 kg and the coefficient of static friction between...