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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Problem of tension force

According to my book, "tension is the reaction of a rope when it is stressed". Then it also said when the string is massless, tension is same everywhere. However in a,let, pulley-rope system,when ...
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3answers
66 views

Does gravity stack?

If I am standing on a planet on the opposite side from its sun will I feel the downward pull of both the planet's gravity and the star's gravity? In other words, does gravity "stack" (Any D&D ...
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0answers
24 views

How do I know which force to use in moments calculation?

I'm working on some Statics problem, with the method of joints, etc and for all of them, we use sum of moments = 0. However, I'm very confused about which forces I should use to find the sum of ...
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1answer
21 views

Impulse on adjacent objects

Let's say two objects are sitting adjacent (in contact) to each other. If we start pushing one of them, we know that both the objects move, remaining in contact to each other. But let's now consider ...
2
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2answers
51 views

How does weight add up to press on things?

I think I understand how pressure works with gases. More molecules bouncing around -> more random impacts -> stronger force. But I realized to my embarrassment that I don't understand how solid ...
1
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1answer
37 views

Strength of strong nuclear force vs distance?

Is there at least an approximation of the decrease in strong nuclear attraction vs distance from the center of the nucleus?
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1answer
40 views

What force counteracts friction when a block is pulled?

Firstly, I understand and apologize that this is more of a physics question than a math question. I noticed that when I pulled a book out from under a pack of gum, the gum stayed largely in place (it ...
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3answers
1k views

The physical definition of work seems paradoxical

So this is possibly a misunderstanding of the meaning of work, but all the Physics texts, sites, and wiki that I've read don't clear this up for me: In the simplest case with the simplest statement, ...
2
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0answers
56 views

Gravitational atraction of fast object [duplicate]

Let's imagine a asteroid that travels with 0.99999999999999999c. (I know it's impossible). Anyway... Relativistic mass of such object would be almost equal to earth's stationary mass. Now let's ...
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0answers
37 views

Inclined conveyor belt mystery

The situation An inclined conveyor belt with topmost point $h$ height above the ground receives sand at a constant rate $X$ from a container at a negligible height above the lowermost point of the ...
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0answers
39 views

Moving object under water [on hold]

If a cube of side 20ft is at 50 ft below in fresh water and it extends 20 feet horizontally giving it a measurement of 20 ft high, 40 ft long by 20 ft wide and the moving section weighs 700lbs. How ...
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2answers
42 views

What point of application of force ensures more acceleration in a rod?

Suppose there is one rod and a force F is applied in two cases: Case 1: exactly at the middle on center of mass Case 2: at one end of rod In which case would the center of mass of rod be accelerated ...
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1answer
54 views

How to calculate energy to start movement?

So let me try to explain a little bit. Lets say I have a robot on wheels. I want this robot to push a block. Lets say the force to produce in order to move that block is 100N. How much energy will I ...
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1answer
60 views

Why does Newton's Third Law not preclude any motion at all? [duplicate]

When walking, if I apply a force of 2N on the earth, the earth applies a force of 2N back on my feet due to Newtons 3rd Law of Motion. These 2 forces are equal in magnitude but opposite in direction, ...
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2answers
70 views

Electrical force between two objects

I tried to solve the following problem: There are 2 objects . The object m1 with charge q and the object m2 with charge q.(same charge).The object m2 is connected with a rope to the ceiling. at the ...
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5answers
228 views

Acceleration in $F=ma$

I tried to ask this question in Electrical Engineering Stackexchange but was told I was better asking here. Newton's Second Law of Motion states that the vector sum of the forces $\mathbf{F}$ on an ...
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0answers
18 views

Lee Yang force and cosmology

The text I am reading (Stars and Relativity by Ya. B. Zel'dovich) discusses the possible existence of a repulsive force proportional to total baryon number. At the time of the book's publication it ...
0
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1answer
27 views

Force felt by capacitor mounted on printed circuit board

I have a printed circuit board with a surface mount electrolytic capacitor soldered to it. It has two spindly legs that hold up this can, so it can move back and forth on the legs' axis just slightly. ...
2
votes
2answers
28 views

Electrostatics - Inserting a brass plate between two charges

The question is: if I were to insert a brass plate between two charges, what will happen to the force between the charges? Would it increase, decrease or stay the same? Does the brass plate increase ...
1
vote
1answer
33 views

generate force accurately

When we like to produce known forces, we know that standard weights acting vertically on a object creates a known force. Now, what are the other methods to generate forces with accuracy. It is a DIY ...
3
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0answers
61 views

Why are interactions always mediated via bosons (as opposed to fermions)? [duplicate]

Weak, Strong and electromagnetic force are mediated via bosons. I've come across the Walecka-model where the exchange particles are $\sigma$ and $\omega$ mesons; bosons again. why are interactions ...
1
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2answers
58 views

who will win a race between man, horse and car of same power

Other day I got into a chat with my friend on work power and energy where he asked an intelligence related question the question was like this if a race was conducted between a man a horse and a ...
2
votes
1answer
35 views

Why doesn't the air in a Standard Diving Dress crush you?

I recently watched a Mythbusters episode where they tested decompression in a tethered diving suit (which I believe is a Standard Diving Dress). When they removed the air pressure, the suit crumpled ...
0
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2answers
50 views

Rotational behavior of objects in zero-g with forces [closed]

I would like to know how this object would rotate in free space out of curiosity. Below is a diagram of the object. It is of uniform density and has a center of mass in the center of the object, ...
0
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1answer
75 views

How to discover the $F = m\cdot a$ equation from scratch? [duplicate]

Is there a paper or a book that conceptually 'discover' the Newton's famous formula? I've been thinking about this equation, and I really don't know it for sure. Did Newton empirically noticed that ...
1
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1answer
26 views

Work done in pulling a rope from a boat

A boy sitting on a boat pulls on a rope with a constant force $F$ over a duration of time $t$. The other end of the rope is either tied to a bridge or to another freely floating boat of equal mass. ...
5
votes
3answers
75 views

Will a drop of liquid flow from from the wide opening to the narrow opening of a thin funnel by the effect of air pressure?

We have a funnel that is thin enough to keep a drop of liquid inside it as shown in this figure. Assuming that the funnel is placed on a horizontal table, will the drop flow from the left side to ...
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vote
4answers
70 views

Basic buoyancy question

If I have a cup of water filled with air at the bottom of a pool, then when the cup is "upside down" the air doesn't leave because the water pressure is pushing it up against the top of the container. ...
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1answer
47 views

Figuring out the time period of an Atwood system

SO I was working on Atwoods, when I came up with the following problem, It is more complicated but i should understand this simpler scenario first. As shown in the diagram above, (Atwood machine), ...
1
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0answers
26 views

Forces and acceleration due to an angle that varies over time [closed]

I'm having difficulty figuring out how to set a problem up. The problem is as follows: A $5\ kg$ block is being pulled along a frictionless floor by a cord that applies a force of constant magnitude ...
0
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3answers
70 views

Force and Newton seeking intuitive explanation

Force is explained as a push or pull, feels quite intuitive at first. My question is if an object accelerates over distance of $100$ meter hits a car, and another object of same mass at same ...
2
votes
4answers
279 views

Why can't the work done by a non-conservative force be zero?

Why can't the work done by a non-conservative force be zero? The displacement along a closed path is always zero. So, whatever be the type of force, variable or constant, the work has to be zero. Why ...
0
votes
1answer
29 views

Can $M_3$ move upwards and $M_2$ move to the right?

Can M3 move upwards and M2 move to the right? in the solutions they assume this, but I find it impossible, it doesn't make sense physically. I get the answer wrong if I assume M3 moving down and M2 ...
2
votes
1answer
66 views

What is equation to find force of magnetic attraction

I was wondering as a student, when I was playing with magnets I thought like Gravitational force equation of Newton's Gravitation Theory, can we also calculate force of an magnetic attraction on an ...
0
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1answer
27 views

Terminal Velocity of buoyant object

I'm trying to figure out how much distance does a ball of balsa wood covers until reaching terminal velocity, being released from a bottom of a pool. To my understanding, I need to first figure out ...
2
votes
1answer
39 views

What is the relationship between Force and Kinetic Energy?

I am an Middle-School (Grade 8) student, who is self-learning classical mechanics. I saw this equation from Classical Mechanics: $\vec F=m \vec a$, the following equation is pretty straight forward ...
1
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1answer
68 views

Gravitational Force (conceptual) [duplicate]

Why is gravitational force always an attractive force? And is the Newtonian formula of gravitational force applicable for very small particles like electrons and protons etc.? From Formula of ...
0
votes
1answer
41 views

Does a Force on the block $M_1$ in this diagram have an effect on the block $M_2$?

Suppose we have two blocks: There is no friction. Does $F$ has the same effect on $M_2$?
2
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1answer
52 views

Falling off a chair, how best to save yourself

If I consider a man sitting on an office chair that reclines backwards iff you lean backwards. What could be done to prevent hin from falling? a) raising his legs till they are parallel to ground. ...
1
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3answers
47 views

Doubt in collision

If a ball under the influence of gravity falls straight down from a height h, collides elastically with the floor, at the instant of collision, what forces does it experience? Shouldn't the floor ...
4
votes
4answers
273 views

Is there work being done if no displacement occurs?

So the definition of work is $W = \vec{F}\cdot\vec{s}$. Say I have a point mass which is being pushed on both sides by equal forces and therefore does not move. Does this mean that no work is being ...
8
votes
4answers
411 views

On the definition of work

Work is defined as $$W = \vec{F}\cdot\vec{s}$$ But what what exactly is $\vec{s}$? Is it the displacement of the body on which the force is being applied? Or is it the displacement of the point of ...
2
votes
2answers
72 views

Metric expansion of space and Newton's second law

I wanted to ask the following question: If the expansion of the universe is really accelerating, does that mean a certain force applied on the universe? (According to Newton's second law) What kind ...
4
votes
1answer
84 views

Why doesn't a wall move when you push it if there's space behind it?

In the first screen you can see that if a person were to push a wall within a typical household the wall would not move while keeping themselves tractioned to the floor. If you push hard and do not ...
0
votes
0answers
59 views

How do I use the direction of a cross product?

The question is: An electron is projected at a speed of $3.70×10^6\text{ m/s}$ in the $u=\frac{(i+j+k)}{\sqrt3}$ direction into a uniform magnetic field $\vec {B} = 6.43 i + 3.43 j −8.29 k$. ...
1
vote
1answer
55 views

Which areas of physics are related to the act of playing drums?

I'm musician (drummer) and I'm trying to figure out what can I study (related to Physics) for better understanding of the drumsticks and wrist movements, the force applied and the better way to apply ...
9
votes
3answers
302 views

What does Feynman mean when he says that $F=ma$ is not exact?

Chapter 12-2 in Feynman Lectures Vol. 1 states: In fact the law, $F=ma$ is not exactly true; if it were a definition we should have to say that it is always true; but it is not ... First, ...
18
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1answer
491 views

What determines the speed of waves in water?

While I was walking my dog this morning, I passed over a canal filled with boats, barges, and kayaks all of different masses and moving at different speeds. I noticed that all of these vessels left ...
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1answer
22 views

Masses and Pulley

I have a two mass and a pulley system as shown here: I have the following two questions: First, why does $\dfrac{d^2}{dt^2} y_p$ is not zero, i I mean I don't understand why does $ y_p$ is going to ...
0
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1answer
43 views

How are contact forces electromagnetic forces?

How are contact forces electromagnetic? What are they: Coulombic forces between polarized molecules in contact? Or they are the magnetic forces due to the motion of subatomic particles? I also would ...