Laws Definition and 1000 Threads

A truck driver is carrying a crate of eggs to a local gorcery store. When the driver gets off the highway, he makes a sharp left turn. According to Newton's Laes, what will happen to the crate of eggs? a. The crate will slide to the right in the truck. b. The crate will slide to the left in...

Homework Statement The temperature of a fixed mass of gas drops from 127 C to 27 oC under constant pressure. Find the ratio of the new volume to the original volume. C. 3:4 D. 4:3 E. 1:1 A and B arent here because i have gotten them wrong. Homework Equations Ideal gas law: PV=...

Just thinking about this and I will say I do not know anything about cosmology or physics beyond what is common, but my question is, could the laws of physics, specifically how particles interact/behave, have evolved right after the big bang so that it started out with a simpler set of laws and...

1. A chain of mass M and length L is suspended vertically with its lower end touching a scale. The chain is released and falls onto the scale. What is the reading of the scale when a length of the chain x has fallen? You may neglect the size of the individual links. 2. A smooth wedge, whose...

Homework Statement An object is placed on a scale in an elevator which reads 8kg at rest. This scale shows 9.2kg when the elevator accelerates. What is the direction and magnitude of the elevator's acceleration. Homework Equations F=MA, F=MG, Fnormal=m(a-g) The Attempt at a Solution...

Hi, I am reading up on special relativity and I'm having some trouble understanding how tensors fit into the picture. Its my first contact with these concepts so please forgive me for being very muddled. My main problem is understanding how to see whether a physical law is compatible with...

Hello, in an introductory course on electricity, it is typical to use Kirchhoff's laws to write a system of equations for a complex circuit having several known emfs and resistors from which the unknown currents are then found. Is this something electrical engineers sometimes do in their work...

can kirchhoffs laws be used to analyze simple parallel/series combination of resistors?

Under what conditions is Faraday’s Law independent of Ampere’s Law? I want to say that this is so only in the static case, however this isn't right (or at least there's more to it). What am I missing?

A while back I piggy-backed onto another thread (and then withdrew it as being out of place) an example of a system possibly violating the conservation of energy and momentum (angular momentum directly) - a spinning hollow right circular cylinder placed under frictionless axial compression. Many...

Hi How many conservation laws are there ? 1. Conservation of energy 2. " " momentum 3. " mass 4. " charge ? TIA

Please help i have these two questions and i am Stuck! Question 1 The linear equation you have found (y=.771x+1.609) is in the form of y= mx +c. it should be however more appropreiatly be considered as being in the form, lny = mx + lnA. by using appropriat logarithmic and exponential laws...

Suppose you have a can (like a spray can) in a vacuum. You poke a hole in the can and the pressure from the can pushes it to the right. Now suppose you have a vacuumed can within a pressurized container and then you poke a hole in it. Which way (if at all) does it move? I know this is sort of...

In a certain binary-star system, each star has the same mass as our Sun, and they revolve about their center of mass. The distance between them is the same as the distance between Earth and the Sun. What is their period of revolution in years? T^2=(4pi^2/GM)*r^3 I know that the mass of the sun...

Homework Statement A tractor is pulling a heavy weight behind it by a rope. If, according to Newton's third law, the load is pulling back as hard as the tractor is pulling forward, then why does the tractor move? Something else I don't really get: A fishline will break when a force of more...

It's been 20 years since I took field theory in grad school, and I didn't really understand it all that well even then, so I'm basically looking for a very low-level explanation of the following issue... In the sum-over-histories approach, there is the question of which histories to include...

Homework Statement A cylinder contains a mixture of helium and argon gas in equilibrium at a temperature of 121 C. Boltzmann’s constant is 1.38066 × 10−23 J/K, and Avogadro’s number is 6.02 × 1023 mol−1. What is the average kinetic energy of each type of molecule? Answer in units of J...

Please see attachment for problem. I know Kirchhoff laws and resistors in parallel and series but how do you solve this?

are they fundamental (like the atom was considered to be)? Or might they vary from one region to another?? Might there be an infinite amount of regions with an infinite amount of laws? Does a similar possibility hold for universal constants?

When you sit in the passenger seat, why do you feel pushed up when you make a left turn? Explain using Newton's laws of motion.My Guess: Newtons third law states there is a reaction for every action. So when you turn left the opposite reaction would be you turning right? IDK LOL :|

Hello I've been wondering a lot of why many laws of energy in different branches of Physics seem similar, for example: Kinetic: \frac{1}{2}mv^{2} Spring: \frac{1}{2}kx^{2} Rotational: \frac{1}{2}I\omega^{2} Capacitor: \frac{1}{2}VC^{2} Capacitor: \frac{1}{2}eE^{2} Magnetic...

Hi guys, I realize this can be a rather uncanny occurance when a new member's first post is to ask for physics help on his homework but I've been lurking around the forum here for a while and am now in a really tight spot and thus had to get over myself and finally make an account...

is known that A and B are events. now i asked to decide form the options A-D which one can have the X value. so i tried to use the De Morgan's laws but i am not sure if this is the correct way. so i need help here. thanks.

Let's say there's two people, A and B. Person A hits person B and person A gets pushed back more than person B does. Would be that be exhibiting Newton's Third Law of Motion of Newton's Second Law of Motion?

Homework Statement A large football player student (1.0 x 10^2 kg) applies a 6.0 x 10^2 N force to another equally burly student (1.0 x 10^2 kg) sitting on a sled (13.2 kg). If sliding friction and air resistance (drag) is 99.5 N, find the acceleration of the sled. In addition, how much...

What force is required to accelerate a 10g bullet from rest to 200m.-1 in a rifle barrel 50cm long i don't need the answer just how to work it out

Does anyone have a good website for some questions/answers for Newton's three laws (I'm not sure if he made more, but the inertia, the net force must be zero when something is not moving, or moving at a constand rate, and the for every action there's a reaction). I've got a test tommorow, and I...

Homework Statement As part of my coursework I've had to show that kinetic energy can be written in a certain way. As a cheat I used this as a starting point and worked my way back to the following equation Kinetic energy = \frac{1}{2}m\dot{r^{2}} + \frac{1}{2}mr^{2}\dot{\theta}^{2} r dot is...

Homework Statement Sorry to bother, but I was working through some homework I haven't done (I put a * next to ones I didn't get and I just wanted to post them because I have no idea how to do them): 1. If you are on a bus that is traveling along a straight, level road at 100 km/h, you are...

Homework Statement Newton's 1st Law of Motion A ball rolled across the top of a pool table and slowly rolls to a stop. How would Aristotle interpret this behavior? Galileo? You? Newton's 2nd Law of Motion If a heavy person and a light person parachute together form the same altitude, and...

As the balloon rises, the force of gravity pulls on the balloon, but which force is strong enough to pull the balloon up so that it floats in the air? thanks

We all know that the universe is expanding and for that matter accelerating. Science is now starting to realize that the universe will expand forever and the big crunch will never occur due to recent data of a supernova. My point to all this is, quantum theory states that a vacuum must always...

Hey, It seems like this is impossible because momentum conservation is violated. I had a Q where an electron underwent an energy transition and emitted a photon, and then they asked whether it was possible for the photon to be reabsorbed by the electron to undergo the same transition as...

1) Using Kirchoff's Laws, find all the currents flowing in the cct. 2) Hence, determine the voltages across all resistors and check that each loop complies with KVL

Homework Statement MP 11.44 Sam, whose mass is 75kg, straps on his skis and starts down a 50-m-high, 20degree frictionless slope. A strong headwind exerts a horizontal force of 200N on him as he skies. Find Sam's speed at the bottom (a) using work and evergy (b) Using Newton's laws...

A window washer pulls himself upward using the bucket pulley apparatus shown. How hard must he pull downward to raise himself at a constant speed? The mass of the person and the bucket is 65kg. My attempt: When doing pulley problems, I like to set 'moving to the right' as positive. In this...

Homework Statement A child slides down a slide with a 34 degree incline, and at the bottom her speed is precisely half what it would have been if the slide had been frictionless. Calculate the coefficient of kinetic friction between the slide and the child. Homework Equations \SigmaF...

A train is traveling up a 3.73 degree incline at 3.25 m/s when the last car breaks free and begins to coast without friction. A) How long does it take for the last car to come to rest momentarily? B) How far did the last car travel before coming to rest? Newtons Second Law I know...

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...

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...