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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Tension problem for rotating object? [closed]

when an object (tied to a massless string) is moving in a vertical circle with constant speed, does it have tangential acceleration when it is at some angle (theta) from the vertical? I am assuming ...
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77 views

Ball Bearing Inside a Hollow, Spinning Rod: where is the logical flaw?

As described in the title, suppose we have a frictionless, hollow rod that is rotating in the $xy$-plane with some fixed angular velocity $\omega$. The rod is pivoting around its midpoint. Suppose we ...
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43 views

A shorter impulse-contact period than a rod´s mechanical longitudinal wave propagation period may fail to accelerate the rod?

I have viewed and read several papers related to this subject but cant find any help to understand some seemingly a simple and a straitforward point, about whether a short impulse period compared ...
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28 views

Which force is necessary for providing centripetal force to a rotating gyroscope?

When a gyroscope is precessing around an axis due to a certain applied torque, if we look at the center of mass , it is going around in circular motion. So there must be some force which provides the ...
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1answer
60 views

Moments of vibrating string

I have to calculate first 10 moments for vibrating string with damping, but I don't know how to do it. I read about moments and in definition they mention linear system $$x'=Ax+Bu, \qquad y=Cx$$ with ...
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5answers
256 views

Why doesn't this perpetual motion machine work?

Imagine a non-magnetic tube bent into the shape of a triangle, with two sides forming downhill ramps, and the third side connecting the two ramps. Through this tube travels a metal ball, which is ...
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1answer
77 views

Does Newton's first law apply also to non-newtonian physics?

I think I understand than an example of Newton's first law (intertial frames) would be a single asteroid in vaccum with no other bodies around, a comet in such free space or likewise. Then I think the ...
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1answer
50 views

An alternate approach to find variation of gravitational acceleration with respect to depth of an object in Earth

As we go down the Earth, assuming it to be a uniform sphere abiding only to Newtonian physics, the gravitational acceleration imparted to an object by the Earth goes on decreasing, and decreases to 0 ...
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2answers
42 views

The effect of windspeed on a car

I've worked problems in the past in trig class concerning the effect of wind on the speed of a plane and it's flight path and was wondering if a similar thing occurs with a car. First off, I'm ...
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0answers
15 views

If a nozzle that converges from an inside diameter of 5cm to 3.5cm carries a gas at a VFR of 0.10 m^3/s, what is the change in average velocity? [closed]

If a circular nozzle that converges from an inside diameter of 5 cm to 3.5 cm carries a gas at a volume flow rate of $0.10 m^3/s$, what is the change in average velocity of the gas? (A nozzle being a ...
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1answer
48 views

Modeling wall's behaviour

Sorry if the quesiton is inconvenient, but I judged the physics forum would be the best place to go. My house is divided in two parts by a wall, and there's some tree pushing it, so the wall is about ...
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2answers
54 views

Newton's second law: Calculate distance to accelerate mass with force

Can I use Newton's second law for calculating distance to accelerate a mass with some force? Let's say I want to accelerate mass of 1 kilogram by applying force of 1 Newton from 0 kmph to 10 kmph. ...
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2answers
64 views

Time for launched object to reach point in space

I am attempting to calculate the time required for an object launched perpendicular to the surface of the earth at escape velocity to reach an arbitrary point in space (neglecting rotational velocity, ...
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1answer
45 views

Importance of Powers of Velocity in Classical Mechanics

Is there any general significance to calculated quantities that depend purely on general powers of the velocity of a particle/system/etc? The first power being momentum and the second being kinetic ...
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36 views

Maximum friction force for a wheel to be able to roll

The wheel with mass $M$ and radius $R$ below is free in space (it is not on the ground). A torque $\tau$ is applied to it through an engine. A horizontal force $F = \frac{\tau}{R}$ is also applied to ...
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22 views

How does ground interact with a box rotating around its corner?

I have some questions about how forces $F$, friction force $F_{friction}$, and normal $N$ interact in order to the box below to turn (clockwise) about the red corner, without sliding. The force $F$ is ...
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0answers
40 views

Cable being pulled at more than two points with a load at one end

Pulling a cable through a series of pulleys with a linear actuator Point A- where actuator attaches at the end of the cable (actuator rated at 2001 Newtons of force) Point B- Will also be pulled by ...
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1answer
37 views

Calculating $g$-force in between planets

The g-force is given by $1 + \frac{a}{g}$. The question is that a rocket is accelerating from between Mars AND Juptier at 26.95m/s. The astronaut in focus is 60kg (irrelevant I believe). Using this, ...
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41 views

A Falling Chain

A chain hanging from a string just touches the surface of the weighing machine. The string is burnt, and the chain falls on the weighing machine. What would be the weight registered on the weighing ...
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2answers
113 views

Experiment which shows that Newtons third law is not true for magnetic forces

I am just reading David Morins "Introduction to Classical Mechanics". He writes about Newtons third law the following: It holds for forces of the “pushing” and “pulling” type, but it fails for ...
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0answers
35 views

How to deal with a box on a plane from the perspective of a non-inertial frame of reference?

I'm having a hard time trying to understand how combined translation and rotation happens when analyzed from a non-inertial frame of reference. I've read that second law of motion doesn't apply to a ...
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2answers
36 views

Elastic collisions and conservation of momentum

If you have an elastic collision between objects 1 and 2 and where 'kinetic energy is conserved', does this mean object 1 will always have the same velocity it had before the collision? Or will ...
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1answer
38 views

Units of acceleration & Newton's 2nd Law

I tried to use Newton's second law, $F=ma$, to calculate the acceleration of an object. \begin{align}\frac{F}{m}&=\frac{ma}{m} \\ a&=\frac{F}{m}=\frac{30\,\rm N}{1.2\,\rm ...
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1answer
34 views

Estimate the maximum distance of water spatter

There is a faucet dripping water from height $H$ onto a smooth, horizontal ceramic surface, and I need to give a upper bound of the maximum distance between the water spatter and the point directly ...
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2answers
35 views

Loads in decelerating a falling object

I'm new here and haven't looked at physics in any real depth since high school, 8 years. so apologies for any obvious mistakes. I remove trees in confined spaces setting up rigging systems, I am ...
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1answer
65 views

Equation of motion for system of springs

I need to find the equations of motion for the following system. If $x_1$ is $m_1$'s extension and $x_2$ is $m_2$'s, then, I feel like for $m_1$ we just need to consider $x_1$ giving $$m_1 a_1 = ...
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101 views

Two boxes connected by a rope

Two boxes, $A$ and $B$, are connected to each end of a light vertical rope. A constant force of $70.0N$ is applied to box $A$. Starting from rest, box $B$ descends $11.6m$ in $4.40s$ The tension ...
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2answers
850 views

What does it mean when physical theories are inconsistent?

I am hoping that someone can explain in layman terms why Newtonian mechanics and Maxwell's equations are inconsistent. Wikipedia says that this inconsistency is what led to the development of ...
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1answer
59 views

The forces acting on 2 boxes [closed]

Consider the following figure: The surface is not friction-less. When the force $F$ is applied on mass A: Is the force the mass A applies on mass B larger, smaller or equal then the Force that B ...
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1answer
30 views

What is the definition of inertial mass?

What is the definition of inertial mass? I can see two options, either it's the coefficient associated with the object being accelerated in Newton's 2nd Law, or it's the coefficient relating momentum ...
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4answers
301 views

If a truck collides with a car, can the truck experience a larger force?

I am confused, here is a question: A large truck and a mini bus both have same velocity V and they collide and stop. The collision lasts for 1 second. A) Which one of the two will experience ...
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3answers
80 views

If a body is floating in a static fluid, then the volume of the displaced fluid equal to the volume of the inmerse part of the object (proof)

Suppose an arbitrary body is floating in a static fluid, either totally or partially immersed in it, then the volume of the displaced fluid equal to the volume of the immersed fraction of the object. ...
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1answer
56 views

Why is the slippage constraint for one moving cylinder and one fixed cylinder $r(\phi - \theta)=R \theta$? [closed]

Why is the slippage constraint for one moving cylinder and one fixed cylinder $r(\phi - \theta)=R \theta$? Every time I write it down on paper I get the result $r\phi = R \theta$. I am not sure if I ...
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1answer
60 views

Force applied at the moment of hit

I have been thinking of this problem quite long time, but couldn't find the solution: Assume that we can measure only the velocity, v, of an object with mass, m, when it hits a rigid and stationary ...
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1answer
54 views

Why do we use sine/cosines in Simple Harmonic Motion? [duplicate]

For example, to calculate the displacement of the particle in an harmonic oscillator we do: $$x(t) = x_{\max} \cos(ωt+φ)$$ What do we find out taking the cosine of (ωt+φ)? Example Graph:
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2answers
54 views

Wasted energy applying a torque

In another question I asked how find a way to desucee wasted energy, but I did not get a satisfactory answer. I have changed the setting here which brings us more close to the solution. Instead of a ...
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1answer
74 views

Potential that is proportional to distance

Does anybody know of a treatment of the case where a potential field is proportional to the distance, i.e. in 3 dimensions: $$V(\vec{r}) ~\sim ~ |\vec{r}|~?$$ Essentially the question is: What are ...
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0answers
103 views

Vertical Travelling - Taking Advantage of Earth's Rotation [duplicate]

As per our current scientific knowledge the earth rotates on its axis and it rotates at a speed of 1670 kilometers/hour. This decreases by the cosine of your latitude so that at a latitude of 45 ...
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2answers
44 views

Solving equation of motion with exponential friction term

My friend's kid asked me this question. I have no idea how to solve it since I have stopped calculating mechanics for about 15 years since I graduated from high school. The question is: A boat that ...
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1answer
316 views

Advanced kinematics problem regarding $F = ma$ [closed]

I really need help with this problem. Thank you for your time. Question: Look at the figure below. Derive the formula for the magnitude of the force F⃗ exerted on the large block (mC) in the ...
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4answers
378 views

Is a causal relationship implied by Newton's 2nd Law?

Throughout my time learning physics I have been imbued with the notion that forces cause accelerations, period. Accelerations don't cause forces, and they aren't merely correlated phenomena. By ...
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1answer
67 views

Two-block system acceleration when applying a force in the $x$ direction

Two blocks are connected by a light-weight string that passes over a friction-less pulley (a.k.a. Atwood's machine). Block # 1 (called $m_1$) hangs from the edge of a friction-less table. Block # 2 ...
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1answer
46 views

Spring Powered Car - Which Design Is Best? [closed]

I'm in the preliminary stages of building a spring powered car to race over a distance of 10 metres. It is a yearly event held in my local area and so far we've only seen one spring powered car. I ...
2
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3answers
146 views

When is momentum not conserved?

What are some common examples where momentum is not conserved? This question arose in my mind when I read that a ball dropped from a height penetrates into a bed of sand and that momentum is ...
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3answers
181 views

Armageddon prevention

I was watching the movie Armageddon and it made me think of a few things. We would probably not need to send a crew to blow the asteroid in two, I think we could still send a warhead with enough power ...
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2answers
180 views

“Magic” Speed to Drive Over a Speed Bump: Myth or Reality?

A somewhat controversial aspect of speed bumps (sleeping policemen for those in the UK) is that they arguably cause more loss of life than they prevent by acting as a hindrance to emergency response ...
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27 views

Possiblity of predicting behavior of system when properties described as functions over space?

Suppose I am given a system that consists of a distribution of charged particles(which are all over space and are point-charges). They are described by a set of functions instead of variables. These ...
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116 views

Can you punch a hole in an A4 sheet of paper with your hand?

The Heading says it all. But let me explain it a little further. Suppose you hang a sheet of paper (A4 size), from one end leaving the other end free. Now practically it seems impossible to punch a ...
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1answer
140 views

Calculating time to reach certain velocity with drag force

I was given a problem for homework where we needed to calculate the time for a falling object to reach a certain velocity when accounting for drag force. I did it by setting up acceleration as a ...
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47 views

How torque and friction cause wheel to roll

I apologize if this question has been answered before, but I did not find the explanation that I needed. If a torque is applied to a wheel situated on a frictional surface, what forces cause the ...