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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Newton's Third Law Clarification

Assuming you place an object so heavy on a table that it breaks it, then according to newtons third law the forces must cancel out (equal magnitude and opposite direction), but if this is true, then ...
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Non-uniqueness of solutions in Newtonian mechanics

In The Variational Principles of Mechanics by Lanczos, in section 1 of Chapter 1, Lanczos states that for a complicated situation, the Newtonian approach fails to give a unique answer to the problem, ...
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If there is no gravity, does that mean there's no mass as well?

I have demonstrated that weight only is measured based on the gravitational pull of where you live. For example, the gravity on the surface of Mars is three times smaller than the gravity on the ...
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161 views

Force acting on an object?

You have a bar of metal in an environment with no gravity. A force is applied on one end of it. How does it rotate? There is a non-zero torque on any random point selected on the bar. For example, ...
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237 views

What happened to potential energy?

I was learning how charge can be virtue of a body's potential energy.Meanwhile,I was hung by this question. [gravitational and other forces except coulombic,are assumed to be not acting on the ...
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Why does Newton's third law exist even in non-inertial reference frames?

While reviewing Newton's laws of motion I came across the statement which says Newton's laws exist only in inertial reference frames except the third one. Why is it like that?
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Time to travel distance given acceleration/deceleration [closed]

A body accelerates at 0.2 m/s$^2$ & retards at 0.3 m/s$^2$. Maximum velocity obtained by it is 30 m/s. Find the least time in which it covers 6 km Well, if I do not assume that the body ...
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145 views

Drag/air-resistance impulse

I'm simulating snowfall in a discrete-time physics engine, using this formula for the drag force on a snowflake: $F_d=CAv^2$ (where $A$ is the flake's cross-sectional area and $C$ is a catch-all ...
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147 views

Math / Physics Help - Barrel Pressure and Velocity

Back in 1993 I derived the following equations to calculate projectile velocity and barrel pressure. Recently, I have noticed that I need to double the calculated results in order to obtain real word ...
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721 views

Do objects rotate around the torque vector or its center?

If I have an sphere and I have a torque vector coming out of it at point A. Would the sphere rotate around its center or the axis of the torque vector?
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318 views

Newtons Cradle, Collision Theory

It has come to the point in my computing program now where I have 5 swinging pendulums that are all modified at once by slider values. These values are drawn onto the from and passed through the class ...
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76 views

How can I simulate a rigid bounced from a wall?

How can I simulate a rigid sword bounced from a wall and hit the ground(like in physical world)? I want to simulate a simple animation. The sword is controlled by a center/mass point.(Actually ...
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83 views

Shifting the energy reference level [duplicate]

In non-relativistic QM, does it make a difference if an energy shift is applied to the systems's Lagrangian or Hamiltonian?
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109 views

I'm having trouble wrapping my head around force, and thus acceleration, diminishing with a higher velocity when using a constant power

Here is an hypothetical situation I thought about that I don't understand. Let's say I have 2 identical rockets with a fixed power. These rockets start to race in the same direction using the full ...
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Resultant of two forces acting in the same line

I'm quoting the definition of Resultant of two forces acting in the same line from the book "A FIRST COURSE IN PHYSICS" one of whose authors is Robert Andrews Millikan: The resultant of two forces ...
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156 views

Can I make a rod in the vertical plane move with its one end on the ground in a slanting position?

Consider a rod kept vertically on the ground. I keeps the rod in a slanting position making some angle with the horizontal. Can I now move this rod along the horizontal plane by applying a force at ...
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352 views

Why don't couple forces violate Newton's First Law?

If you have some random object at rest and you apply a couple to it, the net force acting on it is zero. However because a moment acts on it, it starts to rotate. So you had an object at rest, a net ...
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254 views

Calculating torque in 3D?

Say you have a sphere, and you have several torque vectors acting on it, all at different points. Say you have the vector (6i + 3j + 5k) originating from point A, and the vector (3i + 1j + 9k) ...
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150 views

Why does moment equilibrium at one point of an object mean the moment is at equilibrium for the whole system?

In class my prof said that when showing a system is at equilibrium it suffices to show that the moment at one point is zero. Why? Why does showing the moment at a point is zero imply the moment of the ...
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157 views

Why is moment dependent on the distance from the point of rotation to the force?

The formula for moment is: $$M = Fd$$ Where F is the force applied on the object and d is the perpendicular distance from the point of rotation to the line of action of the force. Why? Intuitively, ...
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136 views

In a moving bus will the ball fall behind me when tossed?

Using Newton's law I have to find whether in a moving bus will the ball fall behind me when tossed in air or will come to me only or will fall in front of me. In fact there are two cases; 1- Bus ...
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103 views

Equivalences and derivations in Newtonian/Classical Mechanics

In Newtonian mechanics there are several "laws" and axioms: Newton's Laws Conservation of: Mass, Energy, Momentum, Angular Momentum I know some are equivalent (e.g., conservation of momentum and ...
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Newton's laws of motion

According to Newton's laws, if net force is zero on a particle then the particle is at rest or in uniform motion, and if it is not zero then it is accelerating. So when a car moves on the road, ...
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288 views

Derivation of Newton-Euler equations of motion

I am in search of a simplified version of the derivation of Newton-Euler equations of motion (both translational and rotational) for a rigid body (3D block) that has a body fixed frame and where the ...
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1answer
203 views

The physics equation for a perpetual seesaw

I am trying to create a game that envovles two or more people jumping on a seesaw and propelling each other in the air. I need help with the physics equations Assume no friction no air resistance ...
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1answer
255 views

Why closed bottle change its weight when I put effervescence tablet?

I use several shape, several type of material (glass, metal, plastic), I use two different balances with 0.01g of accuracy. I put oil on gasket, and put upside down (like that I can see if water ...
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232 views

A man pulling himself up on a platform

Consider the following image: Is it possible that the man pulls himself up (suppose the weight of the platform is negligible), or just lift the right part of the platform up? How to analyse this ...
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137 views

Ball on a slope [closed]

I have a lab report, but I can not write it in a correct way. The lab experiment was about a ball rolling on a slope, I have a height of the slope, the distance, and the time in which the ball spent ...
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Mathematical model for this graph of a simplified binary star system?

Unnecessary background for question: I had a school assignment asking us to relate a quadratic equation to a real life example relating to our future dream career, making sure to express the accuracy ...
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Time period of simple pendulum with varying mass

How do you find time period as a function of time for a simple pendulum that is in the form of a hollow sphere that is filled with mercury and there is a hole in the bottom through which the mercury ...
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515 views

Solve a problem of work and energy

A man pulling sled of his daughter by a massless rope, climbing a snowy hill whose slope is equal to 15 °. Considering that the mass of the sled is $4Kg$, the girl's $26Kg$ and $\mu _c = 0,25$, ...
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360 views

Two-block system connected to a spring

Say you have two blocks with masses $m_1$ and $m_2$, where $m_1>m_2$. The smaller block sits atop the larger block. The larger block is connected to a spring, which is then connected to a wall a ...
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361 views

Deriving the rocket equation

Recently I decided to brush on the those parts of classical mechanics that always gave me trouble. One of those parts was the rocket equation so I figured that I would try to derive the appropriate ...
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Question about moments? [closed]

Take a look at this diagram: http://www.chegg.com/homework-help/questions-and-answers/7-pipe-assembly-supports-vertical-loads-shown-determine-components-reaction-ball-socket-jo-q2260091 If you ...
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A force F pushes an inclined plane M with a block on the incline; find acceleration up the incline

So there is an inclined plane of mass $M$ that is pushed with a force $F$. A block of mass $m$ is on the inclined plane that accelerates up along the inclined plane due to the pushing of $M$ by force ...
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391 views

Resistive force proportional to velocity

Find the displacement and velocity of horizontal motion in a medium in which the retarding force is proportional to the velocity. I kind of understand how to do this problem. We know that the ...
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426 views

Does the velocity of a falling object increase as the mass of a object increases?

I am doing an experiment to show the effect on the velocity of a falling mass due to change in mass. How can i justify my prediction that the velocity of the falling mass will increase as i increase ...
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Gravitational Potential Energy (GPE) to Kinetic Energy (KE) transfer in Satellite Orbits

I am stumped by a mundane A Level Physics question (teacher of physics here obviously a bit short of practice!). My colleagues and I are stumped and were wondering if any one could help us. It ...
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1answer
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Racing balls question

My question is related to simulation of racing ball demonstration. http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=142 One ball goes on a straight path, while another one goes on a curved path. ...
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352 views

Finding the velocity of a block down an incline plane after in moves a distance $x_0$

Consider a block sliding down an incline plane at an angle $\theta$ with the horizontal. For the acceleration as a function of $\theta$ I find $$\ddot{x}=g \ \sin\theta $$ My text then claims we can ...
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283 views

Moment of inertia about a tilted axis

I apologize if it seems foolish, I am a beginner. Suppose I am given an object, whose moment of inertia along the x,z axes are known. Suppose it rotates around a tilted axis, ...
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608 views

Two hanging masses connected by springs

I had this problem for a candidacy exam, but wasn't able to get the complete answer. Their spring constants and masses are not the same, find the equilibrium position and frequencies of the system. ...
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109 views

Circumference of a circular path

Suppose a car moves with a constant speed of $20 \text{m/s}$ a quarter of a circle, and completes the quarter in $5$ seconds. One way to calculate the circumference is simply $20 \cdot 5 \cdot 4 = 400 ...
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528 views

Conservation of momentum when friction is present

Conservation of momentum applies when net force is zero. Suppose that there is a system of a canon and a canonball. Total momentum of the system is zero before canonball is fired. Now canonball is ...
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space acrobatics

In the newly released movie "Gravity" the main character is left alone floating in space in spacesuit, in a fast spin. Assuming there are no external forces (no tether, jet-pack etc) the system is ...
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169 views

Why can you add moment vectors?

My book says the following: If the body is acted upon by a system of forces, the resultant moment of the forces about point O can be determined by vector addition of the moment of each force. The ...
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112 views

Forces, Incline, and Mass

A farm tractor tows a $3900 kg$ trailer up a $16^\circ$ incline with a steady speed of $3.0 m/s$. What force does the tractor exert on the trailer? (Ignore friction.) I am having trouble ...
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Nature of frictional force

I was thinking about a situation where a person in standing on the ground with some friction. The frictional force is directly proportional to the normal reaction acting on him by the ground. Assume ...
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Dynamics of counter-rotating flywheels

I've wondered about this for ages. If we create a pair of flywheels that rotate in the opposite direction with the same angular momentum, but are co-located and have the same mass and inertial moment ...
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Would box on the floor rotate?

There is a floor that friction is proportional to its velocity (like $F=-kv$) and there is a box with its width as $l$ and its height as $h$. (you may assume that $l$ is longer than $h$). It is on the ...