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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How can I answer the critical questions of mechanics? [duplicate]

I have passed my 1st year of undergraduate study life somehow I could have managed. But recently I have decided to fill up the emptiness of knowledge over mechanics. Besides I have my studies of 2nd ...
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145 views

If a material is built to handle tension, would removing the tension damage it?

If an object is designed to cope with large forces such as tension, would removing these forces risk damaging the object? For example: The neck of a guitar is built to handle the tension of steel ...
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3answers
196 views

Mosquito in a Bus [duplicate]

My Question goes like this: If a mosquito inside the bus wants to move from back to front, will there be any difference if the bus is stationary or moving (ie extra effort in the latter case?)? ...
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Why does tossing a coin in a train and on a train differ?

Suppose that I am inside of a moving train. I have a coin in my hand and I am standing still. If I toss this coin straight up, it will fall back into my hand. Now, suppose that I am on that moving ...
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216 views

Question related to work done and energy

Suppose you lift a box from the ground over your head. You will be using energy as there is work done. But when you keep the box lifted over your head, aren't you using any extra energy?
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How long will it take to fill a bath tub with oil compared to water?

As everyone knows, the oil is more viscous than water. But, I've been wondering how long it will take to fill a bath tub compared to water. It is quite obvious that oil will take longer. But, how much ...
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2answers
136 views

Rigid bodies - the wheel

As I've been taught lately in my mechanics course: the wheel has a unique property: at every moment of motion, the touching point between the wheel and the ground is not in movement and ...
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0answers
86 views

How to determine the instantaneous acceleration of each box right after the connecting thread is cut? [closed]

Consider the following diagram. The system is in equilibrium. When the red thread is cut, determine the magnitude and direction of instantaneous acceleration of each box? Neglect the mass of the ...
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1answer
123 views

Equations of motion for an object with normal and angular acceleration

I am currently coding something with a moving object and can't figure out the physics with my school knowledge only. I hope this question is not below the standards of this forum. I have a moving ...
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4answers
2k views

Is potential energy and “work done” the same thing?

Is potential energy and "work done" the same thing? If they are not one and the same thing then why is potential energy always associated with "work done"? Could you explain me with some examples?
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45 views

Collapse of wave function

Can the collapse of a quantum mechanical state in general into one the eigenstates of an observable whenever its measurement is made written mathematically? If yes, how?
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2answers
125 views

Is there an alternative to solving the equation for a bead on a hoop with friction?

Given a circular horizontal loop of radius R and coefficient of friction $\mu$, and a bead which slides along the loop with some velocity, determine the initial velocity $v_o$, that should be given ...
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4answers
7k views

How do bicycle spokes work?

As you know, it is quite obvious that Bicycle spokes attach the hub in the centre to the rim. What else do they do? If you compare the wheels today with the ones from ancient times, there are more ...
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3answers
2k views

When is energy conserved in a collision and not momentum?

Consider the following example: A bullet of mass 45g is fired at a speed of 220 m/s into a 5.0 kg sandbag hanging from a string from the ceiling. The sandbag absorbs the bullet and begins to ...
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1answer
64 views

How to calculate the force in an “impulse based reaction model”? [duplicate]

I have a sphere moving forward with v (pre collision) = v1i A second sphere colliding with the first one has its own pre collision ...
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2answers
331 views

Is force a “real thing”, or a tool for explaining changes in measurable phenomena?

My physics text says that force is "an interaction between two bodies or a body and its environment." When an object undergoes acceleration we explain it with a force. But we don't measure force, ...
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1answer
219 views

Satellites and gravitation

A satellite with mass $m$ orbits a planet of mass $M$ in a circular path with radius $r$ and velocity $v$. Due to some internal technical failure, the satellite breaks into two, similar parts with ...
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1answer
334 views

A basic question: what is accelerating voltage? [closed]

Or would it be acceleration voltage? Acceleration sounds like it makes more sense, but my paper says accelerating. What are possible ways you could go about calculating it?
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2answers
105 views

Kinetic energy conservation in a collision

Kinetic energy conservation in collision. In any type of collision type of collision if we take the system to comprised of both bodies then the net external force is zero. So the work done by ...
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2answers
811 views

The Relationship Between Crater Diameter and the Velocity of an Object

I'm doing a design lab, where I have to "investigate the nature of craters formed on sand." I've done some research and figured out that the cube of the diameter ($d$) of the crater formed by an ...
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65 views

Estimating elevation by camera angle

I'm reading this tutorial on kalman filters, Section 7.2, pg 85-86. It reads as follows: You spotted an enemy mortar installation about thirty kilometers away, on a hill that looks about 0.5 ...
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3answers
834 views

Why if the torque equals zero measured from one point in space it equals zero measured from any other point?

I've heard it from two teachers and saw a task with a solution based on this assumption: If the net torque is zero when measured from one frame of reference, it is equal to zero in all other ...
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0answers
100 views

Isn't Newton's Second “Law” merely a definition of force? [duplicate]

Is it just me, or is Newton's Second "Law" in fact no law at all, but a mere definition of force? The concept of force does not exist prior to the statement of N2, and thus it would seem that the law ...
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4answers
651 views

Do centripetal and reactive centrifugal forces cancel each other out?

In order for a body to move with uniform velocity in a circular path, there must exist some force towards the centre of curvature of the circular path. This is centripetal force. By Newton's Third ...
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2answers
69 views

Fixed lever arm spinning under gravity, why am I getting these results?

Suppose there is a lever arm of length $L$, a mass $m$, and it is fixed at one end. The lever is parallel to the ground. So the force acting on the center of mass of the lever would be $mg$. Now ...
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2answers
120 views

Does an object on top of a lever arm have angular velocity at the moment when the lever is released?

Suppose there is a lever arm fixed at one end, and it is parallel to the ground. There is an object resting somewhere on top of the lever arm (the object is not attached to the lever). At the moment ...
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4answers
150 views

Solids: is energy expended in some fashion by, say, a table to keep the top from sinking down against gravity?

A friend and I were discussing this, and couldn't decide. Since it takes energy to physically raise something up above the planet's surface, does it continue to require energy in order to keep it ...
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2answers
545 views

Finding the optimal angle of a projectile motion [closed]

I am trying to solve a task in which I need to calculate the optimal angle($\alpha$) with which the projectile will land the furthest from a height ($h$), so what I basically have is the equations for ...
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1answer
283 views

Applying multiple forces to one object and calculate net movement and rotation?

I'm working on a small game as a hobby project, and I've run into a problem that would seem simple, to me, but that I can't find any information on or solution to. How would one go about figuring ...
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1answer
319 views

Block on an incline moving right with an acceleration [closed]

The situation looks as follows: The incline is moving rightwards with a constant acceleration The forces on the picture are: mg - weight, N - normal force, F - inertial force (already shown), ...
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1answer
97 views

How do I correctly choose signs for a falling particle?

An object falls from a height $h$ above water through air with negligible drag. In the water, the upward buoyancy exactly balances the downward gravitation force. The only remaining force on the ...
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3answers
611 views

Looking for an intuitive understanding of normal force

I understand normal force to be the perpendicular force to a surface of contact. However, I have come across a problem which has caused me to rethink this. My initial understanding of force is ...
2
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1answer
278 views

About Poincare section for the double pendulum

I am reading Prof. Louis N. Hand's Analytical Mechanics. In the chapter about chaos, it introduces the concepts of Poincare section based on the example of double pendulum. Also, it plot the section ...
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1answer
101 views

Angular Momentum Conservation

There's a question I've come across that I've got some confusion on. A drum of mass $M_A$ and radius $a$ rotates freely with initial angular speed $\omega _0$. A second drum of radius $b>a$ ...
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1answer
84 views

What is the appropriate device for measuring energy loss from collision with surface?

The surface of a running track (i.e. cinder or rubber) has an effect on a runner's performance. I would like to get some device for measuring how much energy a runner loses on each surfaces. I've ...
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1answer
58 views

Dynamics of circular motion [duplicate]

If there is a disc rotating about its centre, let the surface be frictionless and if a coin is placed anywhere on the disc (not at the center) why doesn't it fly off even though there is a centrifugal ...
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3answers
186 views

How much up will an object of mass $m$ will be vertically lifted if a constant acceleration $a$ is given so that resulting force is more than weight?

Yesterday My friend asked me a question which put me into a confused state. If a body of mass m is given a vertical thrust of $F$ such that $F > mg$, and the $F$ is allowed to remain applied on ...
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2answers
532 views

Deriving torque equation from Newton's 2nd Law

I'm trying to understand the derivation of the torque equation $\vec{r} \times \vec{F} = I \alpha$. My textbook derives this easily enough from Newton's 2nd Law for a single point with mass $m$ and ...
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0answers
55 views

Mechanics Newtons third law [closed]

In the system suppose that the mass of the lower cylinder is $12 kg$. The system is held at rest in the position shown, with the tape taut and then released. Find the acceleration of a) the ...
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1answer
133 views

Making a cut trough a center of mass, can the masses of the pieces be equal?

Let's say point $P$ is the center of mass of an irregularly shaped object. If I make a straight cut trough point $P$ and split the object in two, is it possible for the two pieces to have the same ...
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1answer
132 views

Are the the elongation the same when one end of a spring is attached to the wall and

Consider there are 2 identical springs. One end of the first spring is attached to the wall and the other end is pulled by a force $\vec{F}$. It is depicted as shown in the first figure below. Both ...
4
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1answer
136 views

How to find positions of $n$ masses in Newton mechanics?

I ran into a problem while doing research. The problem can be described as: consider the original $n$-body problem, and if we fix the position of them(unknowns), no interaction among them, they don't ...
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2answers
138 views

Is Galilei's reasoning on free fall valid?

Galileo Galilei discovered by experiments that all bodies tend to fall with the same rapidity (I use it in an intuitive sense, you can replace it by 'acceleration' used in today's physics language), ...
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2answers
187 views

Minimum acceleration so that mass $m$ falls freely [closed]

A block of mass $m$ rests on a frictionless wedge of angle $\theta$ as in the figure. The wedge is given an acceleration $a$. What is the minimum value of $a$ so that the mass $m$ falls freely? I ...
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3answers
141 views

A reference frame must be non-moving?

I'm tough in school that a reference frame must be non-moving; For example if I take as reference frame the waves of the ocean, i will have the impression that i'm moving, but I'm not. But if movement ...
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2answers
153 views

Is my free diagram of a spring stretched on one end and attached to the wall on the other end correct? [closed]

Consider the following figures. The top one shows the construction of a spring where its left end is attached to the wall and its right end is stretched by a force. The bottom one is supposed to be ...
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2answers
839 views

Is any work done if I walk in a circle?

My friend and I were arguing about this and I was wondering if someone out there could settle this for us. Basically, he and I were walking to buy some stamps. When we were on our return trip he ...
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1answer
53 views

Angular momentum of anistropic harmonic oscilator

A potential given by : $$ V(x,y,z) = \frac{1}{2}m(x^2+y^2+\frac{z^2}{2}). $$ Which component of angular momentum is conserved. An attempt: Angular momentum along z, $ L_{z} = m(x\dot{y} - ...
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2answers
199 views

Why are turns banked?

I have seen everywhere that where on road, on railway track when there is a turn then one side of that road or railway track is below the surface or some what down then actual surface. Any one ...
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3answers
129 views

Example of Torque, Center of Precession

So here's the set up, we have a fence of length $2L$, and a support strut a distance $l$ from the axis (think of a railroad crossing gate). We need to find the best position for the support rod, so ...