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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Euler's equations (rotating frames)

I'm trying to understand the Euler's equations and I'm having problems with rotating frames and on which specific frame is each quantity measured. On the equation $$ ...
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How to calculate torque required? [closed]

Here's my problem diagram: I am working on a hobby project in which a motor is required to rotate a pulley that is connected to a pendulum as shown in the image. The maximum torque, Horsepower and ...
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1answer
22 views

Calculating the change in aceleration the earth feels when you push an object

I am learning newton's third law, and i got to this conclusion, i wanted to know if it's correct (within the boundaries of Newtonian mechanics) Say I'm pushing a cupboard with my body, and I apply a ...
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Force on a Massless String

Suppose we are just pulling a block with the help of a string which is massless. Now since the mass of the string is 0 the force exerted by us is transmitted without being diminished. So the equation ...
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1answer
40 views

Angular momentum definition? [closed]

The definition of linear momentum is this: Momentum is a vector quantity defined as the product of an object's mass, $m$, and its velocity, $\vec v$. So According to that definition,The definition ...
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Moment of Inertia of a thin rod in the shape of a triangle question? [closed]

Question: Find the moment of inertia of a uniform thin wire in the shape of equilateral triangle of mass $M$ and side length $a$ about the polar axis through the centre of the triangle. So I took ...
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Why is the Plane progressive wave equation $y= a\sin (kx-wt)$ for positive direction of x-axis?

Likewise, why is $y= a\sin(kx+\omega t)$ for negative direction? What is the basis/derivation for this?
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How to calculate the acceleration, if the mass-center is not on the force-vector's line (2D)

In a 2D plane there is an object, whose center of mass is at the $P$ point. The mass of the object is $m$. We apply a force $\vec F$ at the point $A$. If the center of mass is on the line, defined ...
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2answers
38 views

How to calculate the maximum speed of an object?

There is a spaceship, whose mass is $100 \, \mathrm{kg}$. The thrust of its rocket is $300 \, \mathrm{N}$. How is it possible to calculate the maximal speed that the spaceship can reach, and the time ...
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2answers
61 views

Doubt on series springs [on hold]

Here is a description of the motion of two springs in series. The premise is that the force on the two springs is the same. This is derived from the following reasoning: when I pull the mass with a ...
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Dynamics of pairwise distances in the $n$-body problem

Consider the $n$-body problem where we are interested in describing the time evolution of $n$ masses interacting through a potential $U$. Let $D$ be the matrix containing all pairwise distances ...
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Why rotating reference frames are not inertial? [duplicate]

Let's say I'm standing on the equator, and that there is no other reference point in the sky. If the planet is rotating, then I measure my weight to be lower than if it is not. But given that I have ...
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The motion-independent definition of force

I think we must be able to accomodate a definition of a force on some particle which is independent of the motion of the particle, for all kinds of forces, to surely verify the statement like 'force ...
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Vertical oscillator with a punctual mass

Ok, this is apparently a simple problem. Consider a mass bound to a vertical oscillator of constant k, at thr equilibrium position, and initial height H. When letting it move by its own weight, one ...
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2answers
61 views

Tension and friction. Cool question

I had an exercise like the image, where block A is pulled by a force F, there is that rope(tension) attached to the block B and the wall, and there is friction between A and B, and A and the ground, ...
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1answer
32 views

Conservation of Angular Momentum for an Object Not Rotating

I have a point mass connected to a string with negligible mass. The point mass has mass $m$ and is moving at a velocity $V$. The string is of length $r$, and it is keeping the point mass tied to a ...
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330 views

What are the accelerations of blocks? [closed]

I've talked with 2 teachers about this situation: one teacher said he was completely sure that B have twice the acceleration of A, the other said he was completely sure they have same acceleration. ...
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3answers
34 views

Relationship Gravitational Potential and the Tangential Velocity of a Satellite

So gravitational potential is given by $V(r)={\frac{GM}{r}}$ and the tangential velocity of a satellite is the square root of $V$, i.e. $\sqrt V$. So how do these two relate, if at all?
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How is the dot product a generalization of multiplication?

I've seen an interesting explanation for lots of what I previously thought were unmotivated definitions in Newtonian mechanics, namely that power is always defined as effort times flow. But when ...
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2answers
49 views

How can one calculate the force and time of impact?

How does one calculate the force and time of impact of a body colliding into a stationery body please? Can one use Newton's 2nd law of motion?
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4answers
72 views

Action is equal to reaction. Then how is a horse able to pull a cart? [duplicate]

Please answer the question in detail. I have tried other websites for answers but was not able to understand properly.
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2answers
64 views

Is the motion of a particle non-analytic?

I really can't understand what happens during the time $t(0)$ to $t(0+dt)$ in the following crackpot arguement: A particle is at rest (in an ideal frictionless world) until $t(0)$. So every order ...
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2answers
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When it is usually taken as $\omega=v/r$, why in this particular case $\omega=v/3r$ is taken?

A circular disc of mass m and radius r is set into motion on a horizontal floor with a linear speed v in the forward direction and an angular speed w =v/3r in clockwise direction .Find magnitude ...
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1answer
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Fluid Mechanics Paradox

This is a deceptively simple problem in fluid mechanics that I can't quite figure out because it produces a paradox. Suppose that there is a straw and a small column of water inside the straw, such ...
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1answer
45 views

Friction of a scissor [closed]

How can the friction by a scissor blade be related to its angle? To be more specific this is the question that I came across. A scissor is used to cut a wire of circular cross section and ...
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6answers
55 views

Resultant forces

In my text book they said that: If no resultant force acts on an object, it will not accelerate; it will remain at rest or it will continue to move at constant speed If an object is at rest ...
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1answer
39 views

Difference between sudden force and impulsive force? [duplicate]

What is the difference between a sudden force which continues to act on the body, and an impulsive force? What would be respective speeds of the body just after time= 0?
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Pulley inertia momentum of inertia

Considering a pulley with some mass, or some friction, How can its inertia (or momentum of inertia) influence the tension on 1 rope? Which part of the rope is influenced? Before or after the pulley?
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3answers
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How can a pulley work?

Assuming $g=10m/s^2$, the $2M$ mass would exert a $20M$ force on $M$, and by newton's third law, the $M$ mass would exert an equal and opposite force of $20M$ on the $2M$ mass. How would this ...
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1answer
20 views

where does deformation take place in a shaft subjected to a torsion?

If we rotate a shaft about an axis it is said to be under torsion. It is also said that there will be a deformation. What I'd like to know is will the shaft actually WARP during the process? If not ...
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1answer
31 views

Strength of the centrifugal force

Let's say you're on a roundabout. When you're radially further away from the roundabout would you feel more centrifugal force or less? I feel like intuitively you'd feel less, but from the actual ...
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1answer
20 views

Normal force and weight

If two books are placed on top of each other on a table, why would it be incorrect to say that the weight on the upper book acts on the lower book? I thought that the weight of the upper book would ...
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1answer
33 views

Question about Thrust; am I correct?

Basically, here's what I understand about Thrust: Thrust is a force. You get it by doing $v\times\frac{dM}{dT}$. Pretty basic, because that's the formula you're given. However, because I'm trying to ...
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1answer
18 views

When to consider friction as an impulsive force?

Suppose a ball obliquely strikes a rough horizontal surface then it experiences a frictional impulse and conservation of linear momentum cannot be done on the horizontal direction. Now consider ...
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23 views

Finding mass with an estimated gravitational force

As asteroids orbit the sun, they experience gravitational force exerted on them by the sun, and they in turn exert a very minute force back on the sun. Because of their small size, asteroids don't tug ...
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Collision time of two particles [duplicate]

The question I am trying to answer is the following. Consider two particles of mass $m_1,m_2$, initially at rest at a distance $2a$ apart. They are attracted to each other via Newton's law with ...
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2answers
81 views

Do mechanical waves also carry momentum as well as energy? [closed]

I have read that electromagnetic waves carry momentum because they carry energy, while energy is equivalent to mass. So they carry momentum. But this explanation is in the context of special ...
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1answer
65 views

Different forms of centripetal acceleration

For a circular motion centripetal acceleration can be expressed as $$a_{c}=\frac{v^2}{R} \hat{u_N}\tag{1}$$ Where $\hat{u_n}$ is the normal unit vector. Nevertheless in the expression for ...
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1answer
35 views

Vector interpretation of Kepler's 2nd law ( r X a = 0 )

I just read the vector interpretation of Kepler's second law and the conclusion put me in a confusion. The interpretation concludes by demonstrating that r X a = 0, where boldfaced r and a are ...
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3answers
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How to calculate projectile path having starting and end point?

I want to show a projectile path between two points (x1,y1) (x2,y2 ) on graph. Here I know two points, start point and end point. I tried solving by taking launch angle as 45 degree, it doesn't seem ...
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4answers
62 views

Why are objects (such as planets) in motion and not static? [duplicate]

I am just curious, why are all the planets, rocks etc in motion? Would they fall into objects with larger gravity if they were not in motion? What is stopping the earth from falling into the sun or ...
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Can a 2 HP motor move a 1,000 lbs flat-bottom boat across a flat material surface? [migrated]

There is a small 13' long x 6' wide, 1,000 lbs (total weight of everything) all-fiberglass white pontoon boat with dual flat-bottom fiberglass pontoons. (Each flat pontoon bottom is 2' in width, with ...
1
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6answers
71 views

Elevator normal force

In the above case, the normal force exerted by the elevator on the box would be $= 10kg * g + 10kg*5m/s^2$, assuming $g = 10m/s^2$, the elevator would exert a normal force of $150N$ on the box. But ...
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2answers
57 views

How is a mass, suspended vertically by two springs in parallel, kept stable? [closed]

Consider a mass suspended vertically from above by two springs in parallel with different spring constants. Wouldn't the tension be different in each spring? How is this system kept in equilibrium?
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Impulse on the pivot of a physical pendulum

Homogenous rod can oscillate around the pivot some distance from the center of mass. Impulse is applied horizontally at some other distance from CM. I guess the time duration while the force is ...
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2answers
47 views

What is the gravitational field lines pattern of a sphere of mass $m_1$ in an open ended box of mass $m_2$?

This Quetsion is inspired by this Fig of a positively charged metal sphere in an earthed metal box:
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1answer
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Amplitude of damped driven harmonic oscillator [closed]

I have a question that I can reason physically but mathematically I am not sure if my approach is correct. The amplitude of the oscillator is: $$A(\omega) = \frac{QF_{0}}{m}(\frac{1}{\omega_{0} ...
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Locus of a point on Euler's disk

I have been struggling to find how a point on the surface of Euler's disk varies with time in $x$ ,$y$ and $z$ coordinates. The disk has a radius $R$ and a thickness say $T$. It originally makes an ...
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Thought Experiment On Newton's Second Law [closed]

Imagine a rectangular area defined using imaginary boundaries in 2D space. It is not moving. Now, imagine a much smaller rectangle entering the bigger rectangle from one of its sides. This smaller ...
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1answer
89 views

Spinning a string with a mass on the end. What makes the mass rotate parallel to the ground? [closed]

Say you use your hand to rotate a string with a mass attached to the end. The string will first become taunt and then the mass and string will move upwards until they are spinning parallel to the ...