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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2answers
51 views

How to draw a formal free body diagram for a object at rest on a inclined plane?

Five choices I made up: a. b. c. d. e. One thing I know immediately is that the vectors have to cancel each other at last so there is no net force acting on it. a. certainly ...
2
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1answer
35 views

Could an internally tethered rocket cause external movement?

Imagine a scenario where a large box is floating freely in space. There is a vacuum both inside and outside of this box. Also imagine that a dormant rocket is inside this box, but it is loosely ...
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2answers
50 views

Vertical circular motion: minimum velocity

In vertical circular motion while finding the minimum velocity at the bottom-most point for looping the loop, why do we take the tension at the topmost point to be zero?
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3answers
60 views

Rate of Acceleration of an Object Pulled by Magnetic Force

Gravity on earth pulls objects toward it with an acceleration of 9.8 m/s/s on Earth until the object reaches it's max potential free fall speed. (I call this terminal velocity though I think that this ...
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0answers
30 views

Forces acting in a system of a bar suspended by two rods [closed]

So, say I have a bar with a mass of $350 kg$ and it is being suspended by two beams (AC and BD). All joints; A, B, C & D are hinged. At a particular instance, a horizontal force of $1500 Newtons$ ...
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2answers
83 views

Does a body always rotate purely about its center of mass? [duplicate]

For example : A rod is held stationary in vertical position on a smooth horizontal ground and then released. Now the center of mass has velocity and acceleration and every point of the rod has some ...
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1answer
143 views

How do I describe and calculate the effect of an impacting object?

My lab studies the physiology of impact injury on biological tissues. I use a pneumatic cylinder to impart injury into a biological sample and then assess the molecular and physiological changes in ...
0
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1answer
37 views

Rocket thrust over time [closed]

I have calculated the thrust of a rocket, and it's burn time for an orbital manoeuvre. I need to know how much force is applied on the rocket every half-second. How would I go about doing this? ...
0
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2answers
47 views

What objects' masses do we need to take into account when calculating force?

In the following problem: A steam engine of mass $3\times 10^4\ \mathrm{kg}$ pulls two wagons each of mass $2\times 10^4\ \mathrm{kg}$ with an acceleration of $0.2\ \mathrm{m/s^2}$. Neglecting ...
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2answers
50 views

Solenoid cannon (coil gun) possibility and recoil?

Similar to my other question If you are to pass a magnet through a solenoid a current is produced in the solenoid due to the magnetic flux. However, if you were to have a magnet sit inside a ...
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4answers
162 views

How far apart do two objects have to be for there to be negligible force between them?

Inspired from the commentary on this question. How far apart do two objects have to be for the gravitational force between them to be negligible? By negligible I mean, that it could never be ...
0
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1answer
40 views

Friction between two bodies placed one above another [closed]

I'm recently facing a bit confusion regarding the friction between two bodies. Suppose there's two bodies, one placed on another. There is frictional force $ f $ between the base body and floor and ...
0
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1answer
44 views

Unification: what does it mean for the forces to become equal?

The Coulomb force constant $k_c$ has si-units of $Nm^2C^{-2}$. The gravitational force constant $G$ has si-units of $Nm^2kg^{-2}$. What does it mean that at very high energies these forces become ...
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1answer
54 views

Is there surface tension between a solid and a liquid?

The molecules of a solid are so tightly bound together that they are fixed in position unlike in a liquid or gas where they may move freely. In that case it seems like the surface tension between the ...
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2answers
104 views

What is it exactly that conflicts when trying to unify all 4 fundamental forces?

Everyone knows that there are 4 fundamental forces: Gravity Electromagnetic Weak Strong At school and university you're taught that no one has been able to unify these 4 fources. However, not a ...
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1answer
27 views

Why does the axle need to be rotated in a turbine generator?

Inside a turbine a wire rotates between the poles of a magnet, i.e. rotating inside the magnetic field, so that the field forces the electrons in the wire to move and generate current. But why does ...
3
votes
1answer
6k views

Calculating electric motor's weight lifting ability knowing power. What else do I need to know?

So, my company works with electric motors, and my boss wanted me to calculate how much weight could be lifted by a motor rated at 750W. I know that I can't just calculate the work done by it without ...
0
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3answers
121 views

What are the forces acting when we squeeze a ball? Free Body Diagram?

As part of my project, I am trying to figure out the forces acting while squeezing a ball. The ball in question is a foam rubber ball (stress ball). The ball deforms when we squeeze & the mode of ...
0
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1answer
37 views

Question about solving Newton's laws' problems [closed]

A questions from my textbook asks me what the force by the pulley on the roof is. In order to answer the question, need I consider those objects hanging from both sides of the rope, or need I only ...
11
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3answers
623 views

Is acceleration an average?

Background I'm new to physics and math. I stopped studying both of them in high-school, and I wish I hadn't. I'm pursuing study in both topics for personal interest. Today, I'm learning about ...
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2answers
32 views

Factors that affect the speed of body? [closed]

I want to know that what are scientific factors that restrict cars to overcome 450km/hr?
0
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5answers
102 views

Pulley system: how can tensions be equal throughout a entire rope if the weights on opposite ends are different? [duplicate]

More weight means more pulling force, and thus more tension force. Like this answer says, however much force you pulling with is equal in magnitude to the tension force. If that is case, how then ...
0
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2answers
53 views

If two bodies move opposite to each other when brought in contact, what is the direction of force of friction?

We know that when a body is at rest and other is dragged over it then a force is produced which opposes the motion and consequently its direction is negative to the force applied on body to produce ...
0
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2answers
51 views

What should the brake force in this problem be? [closed]

Alright so I think I know how to do this but I require help in calculating what acceleration would be in terms of some sort of friction coefficient. So model a particle going down a hill. The slope ...
0
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2answers
54 views

Simulation of a simple robot [closed]

I'm a programmer and I'm working on a simple robot simulator. Of course, the most important part of this simulator, is the physical simulation of the robot. Unfortunately, I have a little knowledge ...
0
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1answer
53 views

An Electron Chasing Another

An electron is held in place in deep space. Another electron approaches with speed $v_0$. When the approaching electron is a distance $r_0$ away from the first electron, the first is set free. The ...
5
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5answers
3k 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 ...
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0answers
17 views

Need help piecing together football trajectory equations

I've done some studying of the physics involved when estimating the trajectory of an arcing football; that is, in American football, not world futbal, per se. I have all the basic building blocks I ...
3
votes
2answers
77 views

Acceleration of a ramp

If we have a ramp and a block on it, and if all the surfaces are frictionless so both the the ramp and block can move. Is the normal force different from the time that ramp is not moving? If yes can ...
3
votes
3answers
271 views

Electric force between charges in two different media

As far as I know, Coulomb's law of electrostatic force is applicable on two different charges situated in same medium. But if two individual charges are in different media (say one charge on a iron ...
1
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1answer
83 views

Magnetic force paradox

Suppose a current carrying wire Is placed in vertical direction. A charged rod is placed is placed nearly horizontally.It is clear that magnetic field due to current carrying wire is inside the ...
0
votes
0answers
21 views

Calculating atomic forces from total force and torque on molecule in molecular dynamics (MD)

I guess this problem applies to any body that is composed of a small number of particles, but for the sake of simplicity and concreteness, let's consider a classical model of a molecule consisting of ...
0
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2answers
46 views

How do suction cups work?

My roommate and I are having trouble agreeing on how suction cups work. Presumably, the ambient air pressure is the only thing which keeps the suction cup attached to the object. When lifting an ...
0
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1answer
25 views

Why is it easier to push someone over by exerting force on their front side than by exerting force on their left or right side?

If I put two clones of normal weight on a beach in the ocean, with one standing perpendicular to the waves, and the other standing parallel to them, the one standing perpendicular to the waves will be ...
0
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3answers
1k views

Different directions of frictional force when objects are rolling

My textbook has two instances of rolling bodies (smooth rolling). In the first, the body is rolling on the horizontal floor with some acceleration of its centre of mass. In this case, the book says ...
0
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1answer
123 views

Inclined plane, circular motion and the friction

Suppose we have a cylinder on an inclined plane of mass $m$ and radius $R$ moving without sliding (so that $\varepsilon = a/R$). Why is the friction $F$ causing the circular motion sometimes lower ...
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1answer
36 views

Tension in the string produced due to pulling vs pushing

I know that tension is produced when we pull the rope, but what if we push it? What would that be called? Is that tension too? Negative tension?
1
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2answers
56 views

Which moment of intertia do I need to calculate torque

I'm trying to calculate the torque needed to rotate an array of solar panels. I've found some formulas for calculating torque, but they require moment of inertia. I designed this array in Autodesk ...
0
votes
1answer
379 views

Two body particle problem with reduced mass

When we have two bodies and a central force acting towards the center of each other, we could treat the whole problem as a one body problem by introducing the relative coordinate. My question is, when ...
2
votes
2answers
343 views

Loads in decelerating a falling object

I remove trees in confined spaces setting up rigging systems, I am keen to look at the science behind it in more depth so far the formulas that I have found don't take into effect the ongoing effect ...
0
votes
1answer
41 views

Explanation about friction force directions of two moving bodies in contact

can someone explain me why in this scenario (picture below) we have a friction force Ftr12 in the same direction as movement (left part of the picture, case 1 ) and how these directions of friction ...
1
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4answers
89 views

Reduced-gravity flight (A300 0-G): what is actually reduced?

I doubt I can hide from the effects of gravity when I'm close to Earth. We usually don't question this biker is fully experimenting gravity: Source. But with the well-known "reduced gravity" ...
0
votes
3answers
7k views

Simple rope tension problem

I have this really simple rope tension problem that can be solved for seconds using simple logic. I know what the answer is, I know why it is, but I cannot write it down and explain it mathematically. ...
1
vote
1answer
67 views

Accelerate neutral particles

I know it is not possible to accelerate particles via the Lorentz force $F=q(E+v\times B)$, because $q=0$. However, the magnetic moment $\vec\mu$ for such a particle usually is $\neq 0$. Is there a ...
-3
votes
6answers
110 views

A contradiction statement to $F=ma$ [closed]

If I thrown an object of mass 1 kg up in the air it will always fall with an acceleration of 9.8m/s. If I throw it very high up in the sky, it falls with a greater force as compared to if i throw it ...
2
votes
4answers
653 views

Confused about Newton's 3rd law

I am confused about Newton's 3rd Law. If a person jumps off the ground a force is applied both to the person and to the ground. However, as $F=ma$ acceleration experienced by the Earth is much less ...
1
vote
5answers
740 views

Why is it easier to go uphill on a lower gear?

In cars as well as bicycles, when we are on a lower gear, the driving wheel (the one on the wheels) has a bigger radius compared to when on a higher gear. So on a lower gear the bike/car would move ...
3
votes
2answers
192 views

How to use an accelerometer to correctly quantify the magnitude of vibrations

Consider the following setup: An accelerometer is placed inside a helicopter, measuring $g$ values along three axes $(x,y,z)$ every $10~\text{ms}$ (100 times a second), during a helicopter flight. ...
0
votes
3answers
462 views

Are there any non dissipative-non conservative forces?

Although the question stands for itself, I would like to know that if the answer has to be no then does any particular law forbids the existence of such forces; and if there are such forces then what ...
0
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2answers
98 views

Forces Create Angular Acceleration And “Straight” Acceleration - But How Much Of Each?

Let me set up the following problem for a rectangle floating in space: We know its dimensions. We know its mass. There's a force pushing it for a known amount of time - we know the angle & ...