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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58 views

Is it correct to conclude the absence of ghosts from Newtons laws? [on hold]

In fall 2006, an award-winning physicist was quoted in USA Today declaring that ghosts cannot exist. They cannot walk among us, he said, because their feet would need to apply pressure on ...
0
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1answer
20 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, ...
0
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0answers
27 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 ...
3
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0answers
39 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
21 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 ...
4
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1answer
31 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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0answers
14 views

how do I resolve this velocity into components? [on hold]

my problem is: And this is the diagram I drew to resolve it into its constituent R and theta forces: So I get \begin{align} V_r &= - V \cos \theta \\ V_\theta &= V \sin \theta ...
2
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0answers
25 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 ...
2
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2answers
25 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 ...
3
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1answer
43 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 = ...
2
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0answers
45 views

How can I calculate the rotational force and motor HP needed to lift a 5lb sheet from a horizontal position to a vertical position from one end? [on hold]

Essentially, I need to know the following: How do I calculate the rotation force along a fulcrum? Is there an equation? What is the weight of a 5 lb object at the fulcrum if the fulcrum is located ...
0
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0answers
21 views

How to measure how much force to move an object? [on hold]

I am calculating using relativistic in my example, and since an object gets heavier as we increase the velocity by: $$m_{new} =\gamma m_0 = \frac{m_o}{\sqrt{1 - \frac{v^2}{c^2}}}$$ where $m_0$ is ...
1
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0answers
54 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 ...
8
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2answers
798 views

What does it mean when physical theories are inconsistent?

I am hoping that someone can explain in layman terms what it means that Newtonian mechanics and Maxwell's equations are inconsistent. Wikipedia says that this inconsistency is what led to the ...
0
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1answer
43 views

The forces acting on 2 boxes [on hold]

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 ...
1
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1answer
28 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 ...
3
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4answers
282 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 ...
0
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3answers
68 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. ...
0
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1answer
49 views

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

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 ...
2
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1answer
53 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 ...
0
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0answers
37 views

minimum rope stiffness to keep person from touching ground(hooke's law) [on hold]

I thought a lot about this problem (However it's must be very easy ) At first, i would write the statement of problem and then my wrong solution. statement: Find the minimum stiffness of rope,so ...
0
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1answer
47 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
48 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 ...
3
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1answer
70 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 ...
0
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0answers
95 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 ...
1
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2answers
39 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 ...
1
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1answer
218 views

Advanced kinematics problem regarding $F = ma$ [on hold]

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 ...
-4
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0answers
30 views

Can human body survive a negative acceleration of $ 250m/s^2$ [on hold]

Can the human body can survive a negative acceleration trauma accident because of a sudden stop if the magnitude of the acceleration is less than $250m/s^2$. If you are involved in an automobile ...
2
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4answers
334 views

Is a causal relationship implied by Newton's 2nd Law? [on hold]

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 ...
0
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0answers
9 views

Convex and Concave Bridges forces [on hold]

What are the forces acting on a car when travelling in a concave and convex bridge?
0
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1answer
33 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 ...
1
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1answer
31 views

Spring Powered Car - Which Design Is Best? [on hold]

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
130 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 ...
2
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3answers
160 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 ...
2
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2answers
149 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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2answers
25 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 ...
1
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2answers
70 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 ...
3
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1answer
48 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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0answers
35 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 ...
1
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0answers
55 views

Tension Problem: Solve for T for two sliding blocks connected by a string [closed]

The problem: Two blocks made of different materials connected together by a thin cord, slide down a plane ramp inclined at an angle θ to the horizontal as shown in the figure (block B is above ...
1
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2answers
133 views

What causes a tall box to tip over on an inclined plane?

I'm wondering what makes a tall box rotate about its edge (the red point on the figure below) on a inclined plane (with or without slipping), when subjected to forces of gravity and friction only: ...
1
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1answer
42 views

Static and kinetic friction [closed]

Say you have block1 on top of block 2 and the whole system is accelerating toward the right at a certain acceleration. Due to inertia block 1 wants to move backward to the left so there has to be a ...
1
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1answer
33 views

General potential of rotating system

I'm new here at the physics site, and not really that deep into the area of which i'm going to ask a question about now. Therefore please feel free to ask clarifying questions. I'm trying to deal ...
6
votes
1answer
53 views

Movement of a cylinder filled with water

Not long ago I was pretty bored at a dinner and I started playing with a water bottle that was not empty: I've been quite interested in its behavior when putted on its side and pushed: the bottle of ...
1
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1answer
87 views

Electromagnet force equation clarification

So, from a previous previous question, I know what plane the force from an electromagnet will affect a ferromagnetic material in. I thought that would be enough, but working through some problems ...
1
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2answers
32 views

Diagram of forces exerted on objects

Assuming that there is an interaction between 1 and 3 (they attract each other), what are the forces between 1 and 2? I know it is as if the force acts on a different body (1+2), but I want to know ...
0
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0answers
30 views

Where is the maximum center of mass so it doesn't fall over? [closed]

I have some sort of barrow with brakes, which its deceleration due to the braking never makes the crate slide down: I have found it is $\mathbf{a} \leq g(\mu\cos\theta - \sin\theta)$ (note that it ...
5
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2answers
119 views

Pulling apart two interleaved phone books

The TV show Mythbusters had an episode in which they interleaved two phone books and dramatized how hard it was to pull them apart. (A long time ago, a phone book was a book that had an index of phone ...
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0answers
23 views

Effect of an asymmetric weight distribution on a hack squat machine

In a hack squat machine (see figure above), does it matter if I put more washers on one side? May this asymmetry cause an asymmetry of my effort in performing this exercise? For example, if I put ...
5
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5answers
92 views

Forces while squeezing a toothpaste tube

When I squeeze a tube of toothpaste, I am working with 2 squeeze forces toward tube. What causes the toothpaste to go out of the tube? (instead of remaining stationary)