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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Do heavier objects fall faster? [duplicate]

This question has been asked multiple times here and all over the internet yet I can't find a conclusive answer: Some claim that heavier objects do fall faster: Don't heavier objects actually fall ...
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346 views

Fluid Mechanics Piston Problem

The actual problem: A hydraulic car lift has a reservoir of fluid connected to two cylindrical fluid filled pipes. The pipe directly below the car has a diameter of 1.8 m. the pipe on which the ...
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31 views

Physics books for mechanics [duplicate]

What are the best physics books for learning mechanics? I am in grade 12 and would love to learn in depth about Newtonian mechanics and also maybe get started on Lagrangian mechanics?
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The velocity of a cloud?

I noticed an unusually fast moving cloud this morning. My questions: What is the average velocity of a cloud on Earth? What is the greatest ever recorded cloud velocity? What factors affect the ...
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97 views

Paradox of angular velocity

For a torque-free symmetric top, the Inertia tensor has an inverse $I^{-1}$, and $L=I\omega$. Which implies that $\omega=I^{-1}L$. But since $I, L$ are constants, $\vec\omega$ is a constant. However, ...
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1answer
101 views

Why is body frame angular velocity nonzero?

This question is relevant to Euler's angles and Euler's equations for a rigid body. Why aren't $\omega_1$, $\omega_2$ and $\omega_3 = 0$ in the body frame? How can we measure $\vec\omega$?
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70 views

Finding kinetic friction coefficient

A box is thrown up an incline with degree $\alpha$. the kinetic-friction coefficient is $\mu_k$. the body returns back to its start point. a. prove ...
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4answers
2k views

Is there a way for an astronaut to rotate?

We know that if an imaginary astronaut is in the intergalactic (no external forces) and has an initial velocity zero, then he has is no way to change the position of his center of mass. The law of ...
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0answers
254 views

Elastic Ball Collision and contact angle

For a project I need to make a good simulation of balls moving around in a space. The project will be without any air drag and without losing energy in bounces. Since there is no way to lose energy ...
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2answers
225 views

Conservation of Angular Momentum and linear velocity

I have a problem where a cylinder is moving on a horizontal surface, starting with velocity $v_0$. It is given that its radius is $10\text{cm}$, its mass is $200\text g$ and the coefficient of ...
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2answers
333 views

Angular momentum of a translating and rotating body

If a rod is rotating about one end, does it have pure rotation or do you also consider the translation of centre of mass when calculating its angular momentum? Also, how would one calculate the ...
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1answer
68 views

Why does a particle fall in a straight line?

In Lagrangian Mechanics we choose the path of least action. Given a uniform gravitational field, and a particle of finite mass; and fixing two points the start & end-point we consider all paths ...
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6answers
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Why are rockets so big?

I'm curious why rockets are so big in their size. Since both the gravitational potential one need to overcome in order to put thing into orbit, and the chemical energy burned from the fuel, are ...
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1answer
327 views

Newton's second law, gravity and buoyancy [closed]

A body of mass $m$ and volume $V$ is immersed into the sea. The body moves under the action of two forces: gravity and buoyancy (Archimedes). Gravity force has a magnitude $mg$, where $g$ is a ...
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1answer
85 views

Integration on a general equation for instantaneous angular acceleration

An equation for instantaneous angular acceleration is given as: $$ \alpha \equiv \lim_{\Delta t\to0}\frac{\Delta \omega}{\Delta t} = \frac{d\omega}{dt} $$ The text I am reading says writing this ...
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3answers
168 views

Will an object resting on a rotating platform move in a frictionless world?

Imagine that a pebble is placed on a uniformly rotating, frictionless disk. What will happen to this pebble? Will the disk slide under it and the pebble stay as is? Or will there be a centrifugal ...
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203 views

Direction of friction when a car turns

When a ball moves to the right, friction acts to oppose the motion, in other words, to the left. However, when a car travels around a bend, the friction acts in the perpendicular direction to the ...
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2answers
131 views

Newton's third Law?

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body. Newton's third ...
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2answers
83 views

Work and energy problem [closed]

I am trying to solve the problem (see image), my concern is about the 2 factor, can anyone please help me understand this.
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1answer
215 views

Will a free-falling rod (without drag) rotate?

When we consider a bicycle is turning on a flat plane, we know that there is friction, which provide centripetal force on the bicycle. And we know that the bicycle is no longer perpendicular to the ...
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129 views

Is two cars colliding at 25 mph the same as one car colliding into a wall at 50 mph in reference to injuries?

This question has been asked using 50 & 100 mph reference, see this Phys.SE post and links therein. However, I am interested in the potential injuries to occupants of the autos. As the one going ...
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2answers
126 views

Tension in vertical circular motion

In vertical circular motion we conserve energy for calculating velocities at a point (if initial velocity given). But, energy can only be conserved when forces are conservative. Tension is not a ...
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1answer
319 views

Tension on either side of a massive pulley?

When a pulley has mass, why is tension on both the sides different? Why don't we consider rotation of pulley when it is massless?
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1answer
132 views

Missing centrifugal acceleration

I am trying to get correct equations for acceleration of a point in reference frame A, given position, velocity and acceleration in rotating reference frame B. Let $\mathbf{x}_A(t)$, ...
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2answers
115 views

Can a massless rope accelerate?

Suppose I have an Atwood machine, that is, two different masses connected with an inextensible, massless rope over a pulley. Assuming no friction between the rope and the pulley, the heavier mass will ...
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2answers
142 views

Why do orbital speeds decrease further away from the focus?

Why do orbital speeds decrease further away from the focus? A simple question, but I want to make sure I am understanding this correctly: Is it ONLY a function of the gravity well? As in, the ...
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3answers
151 views

Effect of incoming force on linear vs. angular velocity

First of all, I should note that I'm a programmer and have only an extremely basic understanding of physics; I only know how to explain my question in layman's terms and I apologize if I'm unclear or ...
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1answer
88 views

Can the phrase “Terminal Velocity” be used to describe non-gravity situations?

According to Wikipedia: [Terminal Velocity] is the velocity of the object when the sum of the drag force (Fd) and buoyancy equals the downward force of gravity (FG) acting on the object. Since ...
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1answer
302 views

Equations of motion for a pendulum in 3D?

I am trying to solve for the equations of motion to simulate a pendulum. I decided to use the spherical coordinates. The Lagrange equation is: where L = length of the rope ϕ= angle of the ...
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1answer
91 views

The circumference of the Moon's orbit around the sun?

I know that it orbits the sun in what looks like a 12 sided polygon with rounded corners. But I can't seem to find the radius/circumference anywhere.
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1answer
262 views

Atwood machine problem

Sorry for the bad drawing, but I hope that this will help you get a hold of the problem. Consider an Atwood Machine with a total of two blocks, a mass less pulley, ideal string. One block rests on ...
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1answer
325 views

How Can force exist without acceleration?

From what I understand acceleration does not cause a force, but rather forces cause acceleration, so if I have a ball moving with CONSTANT velocity, that hits a wall, then the wall must apply a force ...
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4answers
126 views

Why force $F$ is $ma$ but not $md$ or $mv$? How can I observe and understand “force” in real life?

As a layman, i can calculate approx "displacement" just by observing the moving object. And accurately by using a simple "scale". Similarly, again, I can calculate angle from origin by using ...
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1answer
96 views

Confusing Classical Mechanics Question

I don't want this to be a "do my home work question" so please tell me how I can make this question helpful for other people. In my physics assignment I found the question below. I'd think that both ...
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2answers
142 views

How is it possible to move something without completely lifting it?

For example, let's assume a chair here: It can be "slid" across the force if we use minimal upwards force, but not enough to actually "lift" the chair. Why should it move? Here's a better example: I ...
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139 views

Maxwell's demon - scaling down from something that seems to work

[I have updated the below description to clarify that the mechanism does not depend on a truly frictionless implementation. Also, since 2 commenters apparently assumed that I was proposing a ...
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5answers
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Person Pushing a Block vs. People Pushing off Each Other - Newton's Third Law

I have read so many forums on this and I still do not understand and it's affecting my ability to move forward with learning physics right now. Imagine the following scenario: a person on a ...
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1answer
130 views

Is there a better, faster way to do this projectile motion question? [closed]

The question is In a combat exercise, a mortar at M is required to hit a target at O, which is taking cover 25 m behind a structure of negligible width 10 m tall. This mortar can only fire at an ...
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0answers
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Confused about elasticity and collisions

I was solving the following problem and the explanation to it confused me. There are two objects with mass $m$ and $M$, respectively. The object with mass $m$ has a velocity of $\sqrt{2gl}$ and ...
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1answer
130 views

In a game of tug of war, what concepts are involved in determining where the rope breaks?

Assume that in a game of tug-of-war the rope ends up breaking. What concepts/factors would contribute to the position of where the rope breaks?
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2answers
754 views

Constant Velocity 'Force'?

According to Newtons second law: F = ma, if acceleration is zero then the force must be zero, but assuming you have an object moving with a constant velocity of say 2 m/s, and that object strikes you, ...
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68 views

Do vortex tubes work with a reversed end plug?

Would a vortex tube still work if instead of a cone plugged into the 'hot' end you had a smaller hole on the 'cold' end? As I understand it, the point of the cone on the hot end is to only allow the ...
4
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2answers
112 views

Work done on stationary rocket

Suppose I have a rocket thats exerts a force (with negligible loses in mass), which cancels out the downward force of gravity. Clearly my rocket could be moving at a constant velocity (ignore air ...
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1answer
357 views

Proving Kepler's 1st Law without differential equations

Is there a way to show that motion of Earth around the Sun is elliptical (Kepler's 1st law) from Newton's laws without resorting to the use of differential equations of motion?
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1answer
176 views

How did Newton find the relationship between force, mass and acceleration? [duplicate]

I have been told always that $F$ is directly proportional to acceleration. My question is that for finding such a relationship there should be source that produces desired force and in which the ...
2
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0answers
86 views

Conservation of Mechanical Energy [closed]

I am currently trying to tackle the problem: A 2.0 kg bundle starts up a 30° incline with 125 J of kinetic energy. How far will it slide up the plane if the coefficient of friction is 0.30? ...
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1answer
135 views

Distance formula in kinematics?

I've always seen it $d = v_i t + \frac{1}{2} at^2$ However, I also saw it as $d= d_i + v_i t + \frac{1}{2} at^2$ where $d_i$ = initial position. This was applied to 2D kinematics. Can anyone explain ...
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2answers
204 views

Intuitive understanding of centripetal vs. centrifugal force

I am having trouble understanding how centripetal force works intuitively. This is my claim. When I have a mass strapped on a string and spin it around, I feel the mass pulling my hand. So, I want ...
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2answers
119 views

Is mass proportional to the displacement from equilibrium in Hooke's law?

If I look at Hooke's law as it's defined in my textbook, it looks like: $F = -k\Delta s$ Therefore, the restoring force of an ideal spring will be proportional to the displacement from equilibrium, ...
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1answer
39 views

Acceleration on an inclined rail [closed]

I have to use $\vec{P}+\vec{R_N}+\vec{F_f}=m\vec{a}$ with $\|\vec{F_f}\|=\mu\|\vec{R_N}\|$ to express the acceleration as $$a_{x'}=g\sin\alpha(1-\frac{\mu}{\tan\alpha})$$ The configuration is (sorry ...