This tag is for the classical concept of forces, i.e. the quantities causing an acceleration of a body. It expands to the strong/electroweak force only insofar as they act comparable to ‘classical’ forces. Use [tag:particle-physics] for decay channels due to forces and [tag:newtonian-mechanics] or ...

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79 views

Friction on a body

Consider a cuboidal block kept on a table with friction coefficient $\mu$. When calculating the friction, we use $f= \mu n$ where $n=mg$ for a horizontal table. But a pressure due to the atmosphere ...
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2answers
678 views

In which direction does mud fly off a moving bike's tire & why?

If a bike moves through a muddy area, mud gets on its tires. Then the mud flies off from the tires. Which forces are acting on it? In which direction does it fly off? On my physics test, I wrote ...
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1answer
33 views

How would change force of gravity? [closed]

How would change force of gravity, impacting some object, when this object is lifted on height $h = 3 \cdot R_3$. The right answer stated as ("decrease 16 times"). I want to know why.
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1answer
11 views

Is the index of time in the unit equivalent to force dependent on the number of dimensions

When the unit of force is represented as $\text{distance per time}^n$ in 3 dimensions $n$ is equal to 2. Is n also equal to 2 for higher or lower dimensions (2D, 4D, 5D, ...) or is it dependent on the ...
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3answers
7k views

Work = Force x Distance vs Displacement

The difference in using Distance vs Displacement is demonstrated in this example: Work = Force x Distance If I carry an object to and fro 10 metres, the work done would be Force x 20 metres. ...
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3answers
239 views

Question on normal force and static friction [closed]

Why is this statement false: If the normal force on an object increases, the static friction must increase? Thank you! Is it because they did not state what normal force is referring to?
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3answers
1k views

Why do non-accelerating objects exert force on each other?

The equation for force is $\vec{F} = m\vec{a}$, where $\vec{a}$ is acceleration. Acceleration is a change in velocity. However, if an object with constant velocity (i.e. 0 acceleration) hits another ...
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2answers
87 views

simple force question

So given this diagram, I was supposed to find the magnitude and direction of the net force on the -10nC charge on the bottom right corner. I found the magnitude by myself using Coulomb's law for the ...
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1answer
94 views

Do we all actually just weigh half of what our bathroom scales tell us?

Here's the reasoning: Newton's third law tells us that every force has an equal but opposite reaction force. So besides my weight pushing down on the scale from above, there's also an equal force ...
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2answers
152 views

Mathematical Proof of Force

I remembered reading an paper a while ago which tried to prove whether force actually exists, or if it a man made construct to aid our understanding of the world. However, I can't seem to find the ...
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1answer
134 views

How does one calculate or even approximate the force observed by a magnet as its dropped inside of a diamagnetic cylinder?

How does one calculate or even approximate the force observed by a magnet as its dropped inside of a diamagnetic cylinder? Wikipedia and Google does not provide much information on this topic. ...
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2answers
932 views

Can we make a force which can oppose earth gravity? [duplicate]

If we are standing on earth, then some force (gravity of earth) is pulling us down. Can't we make a force which can oppose gravity? Can't we make an object of zero mass?
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2answers
252 views

frictional force is nonconservative force [duplicate]

In nature there are mainly four kind of fundamental forces,electromagnetic force is one of them which is conservative force.If friction force is belongs to electromagnetic force then why it is not ...
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2answers
209 views

Gravitational force in a building

Suppose that a person is standing on the top of a multi storey building and at an instant earth's gravitational pull becomes zero.What will happen in the next instant? (Consider only earth's gravity ...
1
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1answer
41 views

Half of a uniform disc suspended by two strings [closed]

Suppose we have a half of a thin, homogenous disc hanging from the ceiling as shown: Given the weight of the disc $Q$, calculate tensions in strings $S_1$,$S_2$. Now this seemed like quite a simple ...
2
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0answers
205 views

Force required to crop/cut a mild steel bar [closed]

I have cropping wedges with a diameter of 4mm cutting either side of a round mild steel bar (17.5mm). These wedges are operated using 2 hydraulic cylinders (6" diameter, 2 1/2 travel) (one for each ...
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1answer
117 views

Coefficient of elasticity of the spring?

I know this might sound a silly question though For a spring that is compressed lets say x meters by a force F N. what is coefficient of elasticity of the spring? We are not given the equilibrium ...
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3answers
494 views

Weight distributions [duplicate]

If a man is standing on two weighing machines (scales), with one foot on each, Will both machines show equal weight or his weight will be distributed in two machines?
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1answer
2k views

Maximum range of projectile launched from an inclined plane [closed]

As we already know the max range if we launch it from any flat surface or from any height but I was wondering what will be maximum range if we launch it from inclined plane. I have made on figure of ...
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2answers
442 views

Why do we feel resistance to gravity rather than the acceleration of gravity?

What's the reason it behaves differently from all other forces? What I mean is, if you're in orbit you're accelerating toward the earth at almost 9.8m/s^2, but you feel nothing. If you are riding a ...
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1answer
976 views

Force in a moving object that is not accelerating

If an object is traveling in a straight direction at a constant speed it has no acceleration, right? So if $F=ma$ and $a =0$ then force should equal 0. Does that mean a car traveling at a constant ...
2
votes
2answers
260 views

Does friction act on a wheel rolling at a constant speed

One of the things I've seemed to have taken for granted is that its the friction the floor exerts on a rolling wheel that prevents slip from occurring. However, I ran into something that challenges ...
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1answer
67 views

What does “interact via strong force” mean?

I was just wondering if the words "strong force" and "strong interaction" are interchangeable? Also, these are referring to "strong nuclear force", correct? Then what does it mean for particles to "...
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1answer
110 views

Force Needed To Maintain Velocity, Increasing Mass

Hoping somebody could give me a hand with this. Unfortunately I haven't taken physics yet, my background is in math/computer science. I'm studying computational science and the problem is essentially ...
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4answers
871 views

What causes a car's velocity to follow the front wheels' direction?

I'm trying to simulate a car with correct physics models. In this example we let the car have a constant speed, and there are no forces (friction and drag) to slow down the speed. Here's a video that ...
2
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2answers
114 views

Formula for balance with three arms?

I'm searching for a way to express the angle of the arm of a balance instrument expressed in the weight that is present in one arm. For a two legged balance one could use the moment formula: moment = ...
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1answer
55 views

Buoyant force on a certain object

Sometimes a certain body is completely immersed in water, but it does not sink deeply, it is stuck in the middle... In this case, is the buoyant force equal to the weight of the body? Why?
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1answer
59 views

Is force exerted by Earth different for different mass?

We know Earth pulls every object by the same acceleration $g$ (say). force exerted by earth $F=m\cdot g$ (with $m$ the mass of the body), so, if $g$ is constant then $F$ is directly proportional to $...
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1answer
53 views

Definition of Force Using Momentum

When we use F = change in momentum / change in time, is that the average force applied? There could be different magnitudes of force applied over time to change the momentum (it could be instantaneous ...
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1answer
128 views

Pressure and force of ideal gas in a leaking container?

Let's imagine you have a container that has a pressure of 10 Pascals inside and a vacuum outside. The container has a volume of a cubic meter and I'm not sure if the temperature matters but lets say ...
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0answers
76 views

Is the acceleration of a soap bubble the standard value of gravitational acceleration?

Is the acceleration of a basic soap bubble the same as the standard value of gravitational acceleration 9.81 m/s^2 when it is dropping in a windless space? I have used the Newton's 2nd law to prove ...
3
votes
3answers
317 views

Force Body Diagrams of object sliding down ramp

So I think I am confusing myself about forces. I know that when something is sliding down a ramp that it will have the force of gravity, normal force and force of friction acting on it. But for an ...
1
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1answer
72 views

A Question on Friction [closed]

And yes, this is not a homework thing.Here's my working.
1
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1answer
75 views

Why two colliding bodies exert varying forces on each other during the course of their collison?

Suppose a bat hits a ball .What is the explanation of why the force is not constant during the course of the collison. At certain instants both ball and bat exert varying degrees of force on each ...
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1answer
174 views

Movement and Rotation of a Inverted-Pendulum-like Object with External Forces

I'm struggling to model the movement of a complex object based on an external force. Let's start with a simple example of what I'm looking for. We have a block $b$ of mass $M_b$, moving friction-...
3
votes
1answer
149 views

Could the 4 Forces Split Off or “Decay” into Other Forces in the Distant Future? [duplicate]

From my basic understanding of popular-level physics articles and books and such, the 4 forces (Electromagnetism, Gravity, Strong and Weak Force) used to be 1 force in the early universe, then split ...
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2answers
241 views

Can the coefficient of friction be derived from fundamentals?

It is common to want to derive macroscopic laws from what we know microscopically - after all, given a (correct) microscopic description, everything larger should follow. Has it ever been done to ...
2
votes
1answer
63 views

To which side will it move? [closed]

Children pull the carousel with diverse forces (as in the picture below). In which direction will the carousel move? Calculate the torque. I have done the following: The torque of the force that ...
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2answers
116 views

Why does a reaction force still allow the thing exerting the force to move?

A $5$ kg and a $10$ kg box are touching each other. A $45N$ horizontal force is applied to the $5$kg box in order to accelerate both boxes across the floor. Ignore friction forces and determine the ...
4
votes
1answer
168 views

You are trapped on a frictionless sheet of ice. Can you escape by inhaling in one direction, then exhaling in the opposite direction?

You are trapped on a frictionless sheet of ice. If you trued to escape by blowing, you would have to inhale eventually, which would counteract the force you gained by blowing. However, if you were to ...
3
votes
4answers
147 views

Why can't I harness normal force?

Lets say I have my palm flat with a book resting on top of it, and I have my feet on the ground. I extend my arm so that now it's kind of difficult to keep the book up. Why doesn't my hand just ...
1
vote
1answer
79 views

Rigid body: internal work null?

I am following an elementary physics course book, namely W.E. Gettys, F.J. Keller and M.J. Skove's Physics (in an Italian translation). In exercises where no non-conservative force acts on a rigid ...
6
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1answer
614 views

Analysis of a card pyramid

Here's an interesting question I thought of. Firstly, picture one of those card pyramids. Hopefully you know what I'm taking about when I say card pyramid, but basically you balance two cards up ...
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2answers
56 views

Describing forces mathematically

Let's say you wanted to write a differential equation for the forces acting on an orange sitting on the table (or any other object) using Newton's second law. Somehow you would have to add up all the ...
3
votes
1answer
172 views

Determining straining force and reaction forces on a beam [closed]

A homogenous beam $OA$ with the length $4a$ and the mass $m$ can rotate in the vertical plane along a horizontal axis through $O$ and is kept in equilibrium by a wire running from the points A and C ...
1
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4answers
231 views

The speed of air rising through a heated tube

I would like to get an explanations of an observed physical phenomena. When a metal tube is placed vertically and heated and the air inside rises, the speed of the air moving through the tube ...
14
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6answers
5k views

Can you ever exert more downwards force than your weight?

So, because I'm a hardcore person, I risked all this afternoon by going out in the wind, the rain and the cold to construct a willow den. Yes, it seems a menial task, but it was actually quite ...
2
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1answer
60 views

Distribution forces

I've got two trees and between them is a rope. When someone about 100kg sits at the center of the rope, what are the forces on both parts of rope (to the left-hand side from the person and right-hand ...
1
vote
1answer
69 views

Where should five charges be placed inside a hollow sphere so as the system has the lowest potential energy? [duplicate]

I want to know the configuration where the system would be most stable.I only know basic Physics & Maths and cannot start solving the problem.I can understand it for 4 charges and 6 charges as a ...
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3answers
96 views

On a scale, why does the heavier object go down?

When you balance a pencil on your finger, I have always wondered, "Why does the heavier part go down, and the lighter, up?"