Newton's third law Definition and 251 Threads

Homework Statement You are standing on scales which read weight in Newtons. A 0.50 kg ball is dropped from a height of 1 m into your hands. Your hands drop from chest level to waist level during the catch, a distance of about 25 cm. Your mass is 62 kg. Assuming that you decelerate the ball...

Ok so I just read this statement as part of an explanation of list using Newton's 3rd law "The amazing thing about wings is that because they are flying through air which is a fluid, the top of the wing deflects air down as well as the bottom of the wing." What I don't understand is how...

If everyone believes that there's an equal and opposite reaction for everything, should the universe go out to a point and stop; or will it end up coming back to its origins?

The lower block in the figure is pulled on by a rope with a tension force of 20 N. The coefficient of kinetic friction between the lower block and the surface is 0.30. The coefficient of kinetic friction between the lower block and the upper block is also 0.30. What is the acceleration of the...

The figure shows two 1.0 kg blocks connected by a rope. A second rope hangs beneath the lower block. Both ropes have a mass of 250 g. The entire assembly is accelerated upward at by force. What is F? What is the tension at the top end of rope 1? What is the tension at the bottom end of rope 1...

[SOLVED] Newton's third law Homework Statement My book gives two forms of Newton's Third Law: Weak Form: The forces exerted by two particles \alpha and \beta on each other are equal in magnitude and opposite in direction Strong Form: The forces exerted by two particles \alpha and \beta on each...

Homework Statement In a tractor pulling contest, a 2300-kg tractor pulls a 4900-kg sledge with an acceleration of 0.61 m/s^2. If the tractor exerts a horizontal force of 7700 N on the ground, determine the magnitudes of (a) the force of the tractor on the sledge; (b) the force of the sledge...

Ok, I'm getting a lot of mixed messages about the reactionary forces involved with the 3rd law. if i push a box at a constant speed with 100N of force, is the friction that resists the motion the opposite but equal (100N) reaction force? isn't the friction force LESS than the push force because...

[SOLVED] Newton's Third Law problem Homework Statement Three boxes, A, B, and C, are positioned next to each other on a horizontal, frictionless surface. An applied force acting on box A causes all the boxes to accelerate at 1.5m/s^{2}[right]. Calculate the force that box B exerts on box A...

[SOLVED] Newton's Third Law problem Homework Statement Three boxes, A, B, and C, are positioned next to each other on a horizontal, frictionless surface. An applied force acting on box A causes all the boxes to accelerate at 1.5m/s^{2}[right]. Calculate the force that box B exerts on box A...

Hi all, I would like to know in which circunstances the third law applies just in the weak form. Thank you DaTario

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 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 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...

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...

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...

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?

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 "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...

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...

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'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...

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

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?

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

Are there any examples of violation of Newton's third law? The two examples that I know are : 1) Two masses moving relativistically apart from each other. 2) Two charges moving in mutulally perpendicular directions. Can anybody further elaborate on these exmaples with proper explanation and...

I hate all of Newton's laws questions. They are so complicated. Can anyone please help me with this question. A boy pushes a lawn mower (m=17.9 kg) starts from rest across a horizontal lawn by applying a force of 32.9 N straight along the handle, which is inclined at an angle of 35.1 degrees...

Question: Mass m1 on the frictionless table is connected by a string through a hole in the table to a hanging mass m2. With what speed must m1 rotate in a circle of radius r if m2 is to remain hanging at rest? My answer: Fnetym2 = T - m2g For m2, a = 0 Therefore, 0 = T - m2g T = m2g...

Three toboggans are attached to each other with ropes. A force of 145 N[forward] is pulling the first toboggan, which has a mass of 42kg. A second toboggan, with a mass of 30kg, is attached to the first second toboggan. A third toboggan with a mass of 24kg, is attached to the second toboggan...

Pushy Astronaut -------------------------------------------------------------------------------- a) An astronaut of mass 70 kg pushes off a satellite of mass 420 kg, exerting a force of 120 N for the 0.83 s they are in contact. What is the speed of the astronaut after they have separated...

So I have a homework question that says: A 100 kg hockey player a 112kg hockey player collide with each other each traveling with a force of 50N. The textbook answer says that the acceleration of the 112kg is 0.89m/s^2 and the acceleration of the 100kg player is -1.0 m/s^2. I'm confused...

One question related 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...

Yesterday, one of my cousins asked me about Newton's third law. In this discussion he asked me this question: Why does not a bullet bounce back after striking the surface of glass as it does in the case of steel, considering that in both the cases the force with which it strikes the glass or...

Why we move foward: The applied force from our foot pushs on the Earth and therefore, according to Newton's 3rd law, the Earth pushes back on me to make me move foward. Yeah, this is like basic material, but just need a verification, is this correct?

Newton's third law states something along the lines of "For every action, there is an equal and opposite reaction." The problem I have is that I don't understand how it stays true for something as simple as pushing a box. If a push the box (action), how can it be giving an equal opposite...

If there was a block on a table what would be the normal force between the block and the table. If you could describe the free body diagram that would be great too.

I can not find the answer for this In a rotating frame of reference, Newton's first and second laws remain valid if we assume that a fictitious force equal to mv^2/r is acting. What effect does this assumption have on the validity of Newton's 3rd law?

hi, Before i begin i am not sure where to put this post wether here or in the general section. Is Newtons 3rd law broken? Neutrinos don't follow this rule. the neutrinos can just pass through particles. so don't they break the 3rd rule? :confused:

Although the equal and opposite forces stated in Newton's third law are sometimes referred to as an action-reaction pair in reality they do not share a cause and effect relationship. They arise simultaneously, abide together and disappear simultaneously. Imagine you are spinning a washer...

hi...my teacher has offered an optional project of creating something that used Newton's third law.. I've been trying to think of something but i don't have any ideas... i have to make something .. and umm it can't be a fan on wheel blowing against a wall because that's the example in the book...

can someone explain to me Newton's thrid law of motion?