Third law Definition and 377 Threads

I am reading Introduction to Mechanics by Kleppner and Kolenkow. I am now reading the articles dealing with conservation of angular momentum. I am not satisfied with the articles dealing with how the third law does not lead to conservation of angular momentum. Could anyone please throw some...

Homework Statement I have this problem for homework and I don't know how to even start. Can someone help? Thanks in advance.A neat and exploitive use of the sun would be to put a space probe into a solar elliptical orbit from the Earth on one side of the sun headed towards a rendezvous with...

Homework Statement BY consideration of the pressure coefficient dp/dt|V determine whether a real system can be governed by the van der Waals equation, the ideal gas equation. Homework Equations pV=nRT ideal gas (p+a/V^2)(V-b)=nRT Van der Walls dp/dT|V=dS/dV|T The Attempt at a...

I have spent a ton of time researching my question but i can't find the answer i know that for every action there is an equal and opposite reaction i know if you have a tire on the ground and when it starts spinning it pushes so that the concret will go the other way but the ground it to...

It says that every reaction there is a opposite and equal reaction. Why do things still move if everything is opposite and equal?

a box of books weighing 325N moves with a constant velocity across the floor when it is pushed with a force of 425N exerted downward at an angle of 35.2 degree below the horizontal . find the coefficient of kinetic friction between the box and the floor. what i do :please see check it the...

Please help me because my teacher has not explained how to do questions involving angles. Blocks X and Y of masses mx=5.12kg and my=3.22kg are connected by a fishing line passing over a frictionless pulley. Show that block X slides up the incline (35.7 degrees above the horizontal) with...

Homework Statement The 1.0 kg block in the figure (attached) is tied to the wall with a rope. It sits on top of the 2.0 kg block. The lower block is pulled to the right with a tension force of 20 N. The coefficient of kinetic friction at both the lower and upper surfaces of the 2.0 kg block...

Homework Statement A 1000 kg car pushes a 2000 kg truck that has a dead battery. When the driver steps on the accelerator, the drive wheels of the car push against the ground with a force of 4500 N. Rolling friction can be neglected.Homework Equations F=ma acceleration of car = acceleration...

Are the forces ALWAYS exactly opposite of each other? Is there a way to accelerate a mass upwards, while having the "recoil" force travel on a horizontal plan or somehow completely eliminated? Any and all information concerning this is much appreciated. Rob

Hi, I was wondering, is Newton's third law true? Let's say I've an electromagnet turned on at a constant intensity for a sufficiently long time for the field to have reached a point some distance away. At that point is another electromagnet, but turned off. Now I turn on the second...

Forces between two current elements and Newton's third law Consider two non parallel wires each carrying a current which located at one plane surface. According to electromagnetic theory, the forces between two straight and solid wires mentioned can be estimated as follow: F= i . (L x B)...

Hello. I'm in year 12 at the moment doing my AS level. I'm having some troube understanding Newton's Third Law. Would anyone mind fully explaining it to me please? Thanks :)

Homework Statement Three blocks are stacked on top of each other inside an elevator as shown in the figure. Answer the following questions with reference to the eight forces defined as follows. the force of the 3kg block on the 2kg block, F of 3 on 2, the force of the 2kg block on...

Homework Statement When I plug in all of the parameters for Halley's comet (from Wikipedia) into Kepler's third law a get a semimajor axis of 38.56 AU when it should be about 17? Can someone else try it and see if I am crazy?Homework Equations The Attempt at a Solution

Homework Statement All small compact car is giving a push to a large van that has broken down and they travel along with equal velocities and accelerations. While the car is speeding up, is the force it exerts on the van larger than, smaller than, or the same magnitude as the force the van...

A comet has a perihelion distance of 0.29 A.U. and an orbital period of 77 years. To the nearest thousandth of an A.U., what is its aphelion distance from the Sun? I know that keplers third law plays a part in this p2=a3 but I just can't plug it in right. I know the answer is 35.908 but I...

Homework Statement A spacecraft on a mission to the outer planets passed through the asteroid belt and imaged an asteroid with a small moon. You are on a proposal team to define a mission to the asteroid’s moon to determine its composition and history and have been requested to estimate the...

Homework Statement Using astronomical units as the unit of length , years as the time , and the mass of the Sun as the unit of mass , the value for k in kepler's third law is 1. In these units , what is the value of Newton's constant of gravitation G? Homework Equations P^2 =k*a^3...

I didn't understand the explanation, and think perhaps the book is wrong. A person is standing on a horizontal floor fells two forces: the downward pull of gravity and the upward supporting force from the floor. These two forces are: I put A) have equal magnitudes and form an...

Hello I am Fusina, I wish to ask you Three questions which bother my mind. Its all about Newton's third Law. Is Newtons third law always obeyed? Is there an example of two moving particles, who's velocities are such that their mutual magnetic force doesn't obey Newton's 3rd law...

My lecture notes had S=A{3nR[ln(T)]/2+nR[ln(V)]}. A arbitary, is the entropy equation for a monotomic ideal gas. The third law demands S->0 as T->0. But as T->0 in the above equation, S -> -infinity assuming V fixed. What is wrong? Or is it the case that S-> -infinity is equivalent to minimum...

Homework Statement A woman is standing on a flat section of ground. Her weight is 500N. Newton's third law states that there must be an equal an equal and opposite force to her weight, which is A. The Earth exerting an upward force of 500 N on the woman. B. The woman exerting an upward...

Calculate the period of the Earth's moon if the radius of orbit was twice the actual value of 3.9 x 10^8 m. a. 1.13 x 10^6 s or 13 days b. 2.3 x 10^6 s or 26 days c. 5.14 x 10^6 s or 59 days d. 6.85 x10^6 s or 79 days So far I got: v=velocity; T=time; h= hieght from surface v=? T=...

Please excuse the newbieness of this question. I recently began studying physics. Does Newton's third law apply in the game of Croquet when one applies force to a static ball between the club and a second ball, thus causing the second ball to continue the force applied by the static ball?

The mean distance between the Earth and the moon is 3.84x10^8 m, and the moon has an orbital period of 27.3 days. Find the distance from Earth of an artificial satellite that has an orbital period of 8.5 days. a. 1.76x10^8 m b. 1.76x10^4 m c. 1.76x10^10 m d. 5.24x10^8 m So far I got: I...

Newtons third law states that for every force there is an equal an opposite force. This doesn't mean that these forces are balanced though? Things like cars or people walking can still accelerate so these forces can't be balanced?

my professor kind of sprung this problem out of nowhere for the class, and I'm having just a little trouble getting started? The problem goes like this: A current wire pointing in the +j direction has an Idl. A second current wire in the +i direction has a different Idl. The question he...

Homework Statement Two blocks are lined up in a row. Block A a mass of 1kg, and Block B with a mass of 2kg. If block a is A is pushed forward by 12N, how much force does Block B exert on Block A. Friction can be nelected. Homework Equations Newtons Third law F(A on B)=-F(B on A)...

Hello! We often have lots of free time on our hands at work when we should be er... working, anyway we use this time to debate questions that none of us are qualified to answer in a 'I'm 110% right B***H' way. So I decided to come here and post a couple of the ones we have been arguing in the...

I don't know but in school I learned it in a different way. I mean in school the Kepler's third law was thought as if all the orbits were circular. But according to the definition its all elleptical, and in the school equation we won't add the planets mass, but here...

Homework Statement "Identify at least five pairs of action reaction forces in the following diagram" Source: http://www.physicsclassroom.com/Class/newtlaws/U2L4b.html problem 2 Homework Equations Newton's third law The Attempt at a Solution 1) Man and monkey 2)monkey and scale...

Beautiful Shahar Hod relax time lower bound---connecting to Third Law The investigation of BHs by Shahar Hod has had a big impact Quantum Gravity. Everybody remembers the substantial hoo-hah about BH resonant frequencies, which was set off by Hod. John Baez had a piece in Nature magazine...

I have a picture provided. You can assume that the table is frictionless. I need an expression for the acceleration of m1.

Is certain that this law not fulfilled in the case of two charged particles moving in perpendicular directions (the force exerted in the particle A by the magnetic field of B is not equal to the exerted one in B by the magnetic field of A) ? Why? Bye!

A Saturn V rocket has a mass of 2.75 x 106 kg and exerts a force of 3.3 x 107 N on the gases it expels. Determine: a) the initial vertical acceleration of the rocket b) its velocity after 8 s c) how long it takes to reach an altitude of 9500 m. Ignore mass of gas expelled and assume g...

Here is the question: Astronauts have connected a line between their 3280 kg space tug and a 6100 kg asteroid. Using their ship's engine, they pull on the asteroid with a force of 490 N. Initially the tug and the asteroid are at rest, 490 m apart. How much time does it take for the ship...

HW Help! I have no idea how to answer these questions!:confused: 1) Newton's second law indicates that when a net force acts on an object, it must accelerate. Does this mean that when two or more forces are applied to an object simultaneously, it must accleerate? Explain. 2) A father...

Hello, I was just searching online and discovered this great forum. Please I need help in sorting out a problem with a non-central potential and Newton third law. This is not a physics homework problem. I'm a graduate student working on this equation as a reserch project and there are...

If you have a object that is about 10^36 less massive than the Earth (about 10^-12 kg) and say it exerts a force on the Earth about 10^-11 Newtons, this would cause the Earth to accelerate about 10^-36 m/s^2. If this object was away from earth, and say if these objects were initial stationary...

I have some homework that is due on Wednesday (so I have some time to finish this), but I'm trying to get most of it done soon. I'm having trouble answering some Newton's laws questions and I don't understand why my answers are not correct. Here is what I have thus far: You push a box...

I'm not questioning his law or anything, I just need to understand a few things about it. I understand the basic concept of the law, for every force, there is an equal force in the oppostite direction. But what provides the reaction force in the following situations? A car driving, has an...

Using Kepler's Third Law, give the formula for the period TX of planet X whose orbital radius RX is twice that of earth, RE. A. TX=(1 Year)x(RX/RE)^3 B. TX^2=(1 Year)x(RX/RE)^3 C. TX=(1 Year)x(RE/RX)^3 D. TX^2=(1 Year)x(RE/RX)^3 My book is not giving me a formula to use, so i a totally...

Hi, I was wondering, what is the status of Newton's Third Law of Mechanics in modern physics? I'm told that it does not always hold. In that case, when and how does it break down? Thanks. Molu

emm, i m new member here maybe i m stupid and young enuf to ask these question, but i seriously nid help from u all to explain to me 1st, if we standing on a weighing machine in a lift, when the lift accelerate downward, the reading of W.M. wil decrease?and when accelerate upward the reading...

What would happen if (if ever) when the action force is greater than or less than the reaction force and were not equal in magnitude and were not equal in size?

Two blocks standing on oneanother are pulled with a force F. There's friction between them. With a certain force F the purple block is standing still on the green one (situation 1) because of static friction. Is the netto force working on the green block F+ static friction of the purple block...

Can anyone help me with this problem? thank-you A box slides down a 39° ramp with an acceleration of 1.32 m/s2. Determine the coefficient of kinetic friction between the box and the ramp

Two gravitaionally bound stars with equal masses m, separated by a distance d, revolve about their cneter of mass in circular orbites. Show that the period is proportional to d^3/2 and find the proportionality constant. I know that in this case, F = mv^2/r and that F=Gm^2/d^2. But where...

Two gravitionally bound stars with equal masses m, separated by a distance d, revolve about their center of mass in circular orbits. Show that the period tau is proportional to d^1.5 Could someone get me started on this? I have no idea where to begin! Thanks!