Newtonian mechanics covers the discussion of the movement of classical bodies under the influence of forces by making use of Newton’s three laws. For more general discussion of energy, momentum conservation etc., use classical-mechanics, for Newton’s description of gravity, use newtonian-gravity.

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3
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1answer
27 views

Does the force on the bottom piece of a hummingbird feeder depend on the height of the water in the reservoir?

Intuitively I would think that the more nectar you put into the reservoir the more weight it will put on the bottom piece (the tray that holds the open pool of nectar that the birds can feed out of). ...
10
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2answers
108 views

Can one rise through a free-falling rope?

I am a little confused about this question. I cannot imagine that it is possible to rise through a rope (assuming inextensible) that isn't fixed in its upper end. But when I solve this problem, I see ...
3
votes
1answer
304 views

Question on Binet's equation

Is there a difference in Binet's equation when the force acting on a body is attractive and repulsive? I mean, if the force has a magnitude $F(r)$, is it Binet's equation always $$\frac{d^2u}{d\...
0
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0answers
32 views

What is wrong with my formulas for a mathematical model of a double pendulum?

I tried mathematics but I've had no response in a month. I wanted to create a computer simulation on Matlab, using a model for a pendulum from this study (A double pendulum model of tennis strokes. ...
1
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0answers
29 views

Rotation of rod [on hold]

A uniform rod of length "L" is free to move and rotate in gravity-free space . when an impulse is given to one end of the rod perpendicular to its length, its center of mass moves with velocity "V". ...
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6answers
2k views

Newton's 3rd law… hitting drywall (which I break) vs hitting a brick (which breaks me)?

According to the Third Newton's law of motion: For every action there is an equal and opposite reaction. So, I understand that if I hit a brick wall with $50\, \mathrm{lbs}$ of force, the ...
5
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1answer
52 views

What causes more damage, a head-on car crash at 30km/h or one car at 60km/h crashing into a stationary one?

Which will cause a greater impact? Two identical cars colliding head on (in opposite directions), each going at 30km/h OR One car travelling at 60km/h colliding into a stationary car (for the ...
1
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2answers
114 views

Sliding blocks problem

My first post here, so I apologize if this is duplicated elsewhere. It IS a "homework" problem, but it's public domain, a posted exam with answers... http://www.mun.ca/physics/undergraduates/...
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0answers
14 views

a spring is stretched 10mm by a weight of 2.0N calculate the force constant k [on hold]

stretched 0.01metres weight of 2.0newtons calculate force constant k calculate the weight of an object that causes an extension of 80 millimetres
2
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1answer
34 views

Extinction level meteor effects on Earth's crust pending on the surface area upon impact

Would it be possible to have a extinction level meteor hit Earth depending on shape to actually create minimal damage if turned on its thinnest area rather than hitting flat? The meteor would enter ...
1
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3answers
581 views

Newton's Second Law Confusion

I don't quite understand the relationship between an object's mass, acceleration and net force. For example, if a car was going to the right at a constant velocity or with no acceleration, does that ...
0
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1answer
5k views

What factors affect the velocity of an object moving down an inclined plane?

If you have a small toy car rolling down an wooden plank, what factors would increase or decrease the velocity of said car. In the experiment my team originally stated that adding mass to the car ...
1
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2answers
452 views

Correct terminology for combined kinematic and dynamic state

The kinematic state is defined as the position and orientation in space. The dynamic state is defined as the associated velocities. What is the correct terminology for the combined kinematic and ...
1
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2answers
51 views

Use of $g$ for centripetal acceleration

I have attached an image above including the question I'm unsure of (part B) In a nutshell, a satellite is orbiting Earth at the surface. Given is $g$ and the radius of the Earth. For part bi) the ...
3
votes
1answer
636 views

Rolling a ball into a cone; what should the forces overall be?

This is my solution to finding angular displacement/velocity/acceleration on cone so far. Consider a cone, with an apex of half-angle $\psi$ pointing down, and a height of $h$. If I roll a ball into ...
1
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2answers
60 views

Question regarding elastic collisions and the conservation of momentum / energy [on hold]

I've been working on this question for a few hours and I cannot quite convince myself that my answer is correct. I've read the relevant section in my textbook, but I guess the lightbulb just isn't ...
-1
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0answers
29 views

What will be the new moment of inertia? [on hold]

Let assume we have a sphere of radius $R$, and we can simply calculate the moment of inertia if we consider the axis is going through the center O. Let's cut a sphere small radius $r$ from the sphere ...
0
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2answers
138 views

Few questions related to Tension

I am struggling with the concept of tension in a rope. Below specific questions. I am understanding tension to be an elastic force between rope molecules. If so, is it fair to say the net tension ...
2
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2answers
138 views

Is sonic boom louder than the sounds that a object traveling at the speed of sound makes, if so why?

Here are the wave-front models for both: I am in an introductory physics course. Just learned about this. I am not entirely sure if sonic boom is louder. But from what I saw, it's loudness is ...
0
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0answers
40 views

High School Physics [on hold]

Two girls are standing on a bridge over a river. One girl falls freely and the other ties a rope to her legs. Both jump at the same time from the bridge. The length of the rope is more than the ...
-4
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0answers
60 views

Why move from Special Relativity to General Relativity? [on hold]

The concept of relativity is simple. Why take Maxwell's equations to a new Special Relativity level with the unproven assumption that photons have no mass? All other physical data (momentum, affected ...
-2
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1answer
37 views

basic question about work exercise [on hold]

I am learning independently from Tobochnik's statistical physics text. He asks a warm up question about work: A person pushes a block up a frictionless ramp. Is the work positive, negative, ...
-2
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1answer
28 views

Force dependence on velocity : Drag

I just listened to the second lecture of Leonard Susskind on classical mechanics where he discussed that force can't be proportional to velocity, since it's unable to retro-dict (predict past). He ...
4
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2answers
1k views

What is the longest distance that can be jumped after swinging from a rope?

In the movie Mission Impossible 3, the main character Ethan Hunt tries to enter a building in Shanghai by swing through the sky, as shown below: The jump consists of 2 sections, the red part, which ...
0
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0answers
19 views

Analysing kinetic energy in different frames [duplicate]

Case A: Say we observe a body X moving with a velocity of 30 on the +x and we(the observer) are stationary. Case B: The observer moves with a velocity of 50 on the -x. The body X is moving in the ...
2
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4answers
281 views

Rate at which a pendulum bob slows due to air resistance?

I know that "perfect" pendulums would be able to swing forever, unperturbed by air resistance. However, since there is air resistance around us, pendulums (swinging bobs) slow down and move closer and ...
3
votes
1answer
54 views

Velocity of satellite to crash into the earth

I was reading through this post today and was very impressed by the response that was given. However, what would have to happen to the velocity in order to collide with the Earth? Velocity of ...
-1
votes
2answers
40 views

Does displacement affect force? [on hold]

I am sorry for being unclear with my previous question. The main topic of the experiment we conducted was about work. As we learned: $W = Fd$ Work, from my understanding, is the product of work and ...
2
votes
2answers
435 views

How do I describe the order of events in spacetime?

In Newtonian mechanics, we have 3-space and time. Time allows us to order events. For example, I hold a ball in the air at time $t_0$. Then I drop it at some later time $t_1 > t_0$. Finally it hits ...
1
vote
1answer
179 views

Is the double pendulum an example of a strange attractor?

Imagine a pendulum to which is attached another one (not necessarily the same length). Does this pendulum, when you let it go (which can be done in many ways but let's keep the total potential ...
1
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0answers
36 views

What really is force? [duplicate]

I know the second law of Newton says $F=ma$ which seems to me the most fundamental expression of the force. In other words, force cannot exist without a "forced" one. It is somehow a "secondary" being,...
0
votes
1answer
115 views

Problem in constraint equations

In this, if I want the acceleration constraint between $M$ and $2M$, I write $AM+2AB$=LENGTH OF STRING, which on differentiating twice gives $a_{m}=2a_{2m}$(which turns out to be correct). However, if ...
0
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3answers
376 views

Are Newton's laws followed in non-inertial frame of references having all their objects and observer moving with same acceleration? [on hold]

Consider a hypothetical scenario. In our universe there are two merry-go-rounds 1 and 2 and a distant planet. There is no other object having mass. There is a robot X on the planet. There are two ...
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0answers
16 views

Simple harmonic motion [on hold]

A body executing shm has 10cm as amplitude and time period is 1.5s. Calculate the time taken by the body to travel a distance 5√3 cm from the mean position. I have used the formula x=asim(wt) And ...
5
votes
2answers
10k views

Understanding tension

I'm trying to understand tension. So here it goes: I'll start from the beginning. Let's assume I'm in space and can move around and apply forces. Let's say a rope is attached to a body(which is in ...
1
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2answers
47 views

Work done by internal forces of a rigid body

I am reading Goldstein's Classical Mechanics book, and I came across that: In a rigid body the internal forces do no work Is this statement based on the assumption that the internal forces are ...
2
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4answers
291 views

Centripetal and centrifugal force

If a stone is rotated with the help of a rope, then both centripetal force and centrifugal force will be liberated. The magnitude of that forces are same, but direction of them are opposite to each ...
4
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3answers
5k views

Uniform chain falls off table Diff EQ

I really need some assistance setting up this problem. any assistance would be a Godsend: a uniform heavy chain of length a initially has length ...
6
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1answer
331 views

Derivation of Universal Variables

Does anyone know of link to the derivation of the Universal Variables? This is in regards to Kepler's equations. The Wikipedia link didn't have enough information for me, and the Colorado page doesn'...
7
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1answer
103 views

Why do icebergs move perpendicular to the wind?

I know it has to do with to Coriolis force and the Ekman layer but I didn't really understand the explanation. From Wikipedia: "Ekman transport, part of Ekman motion theory first investigated in ...
0
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0answers
24 views

Stuck with 2D kinetics problem [on hold]

I've been trying to solve this exercise for the last four hours and I'm totally stuck. The problems goes like this: Given the mechanism in the image, located in the vertical plane, the OB cord ...
0
votes
0answers
11 views

How do rockets fly? [duplicate]

Is it that when a rocket loses its mass due to the escaping gases that results in its acceleration due to the same force acting upwards? If so, how is Newton's Third Law associated with it?
0
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2answers
33 views

Forces on body above body moving at constant velocity [on hold]

Let's say the system is moving at constant velocity. What are the forces applied on B? Is there a static friction force? I find it hard to imagine what is happening to object B. $\Sigma F$ is $0$ on A ...
0
votes
1answer
45 views

How do gravitational sling shots work? [duplicate]

How can an object move faster after leaving the gravity of a planet, should a gain in potential energy by moving away from the planet lead to a loss of kinetic energy? Or am I missing something ...
10
votes
6answers
1k views

Why is Newton's first law necessary?

Newton's second law says $F=ma$. Now if we put $F=0$ we get $a=0$ which is Newton's first law. So why do we need Newton's first law ? Before asking I did some searching and I got this: Newtons first ...
0
votes
1answer
56 views

Conservation of enegry in case of Exploding Projectile [closed]

Consider the following problem : A projectile of mass M explodes, while in flight, into three fragments. One fragment of mass $m_1 =\frac12 M$ travels in the original direction of the projectile. ...
-2
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1answer
142 views

Why is the object's maximum speed at $x=0$ for spring? [closed]

My book derives velocity of the hanging object of a horizontal spring (on frictionless surface) as a function position: $$v=\pm \sqrt{\frac{k}{m}(A^2-x^2)}$$ and shows the maximum speed is at when x (...
1
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2answers
159 views

Normal Force in Circular Motion

In the above diagram, sec 1 (on the left side), an object of mass $m$, after releasing from rest from a slant track, continues into a vertical circular track. At a random position on the circular ...
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0answers
40 views

Friction and movement in a system with body above moving body in newtonian mechanics [closed]

I have a problem in analyzing movement with friction involved. I do not know how to correctly analyze systems as such and what is the correct view. I have tried to answer the several question below. ...
-1
votes
1answer
37 views

understanding kinetic friction [on hold]

I have a pen on my table. I apply force horizontally to my pen. The force I apply is stronger then the maximum static friction so it moves. I move the pen at constant velocity. Now if we look ...