# Tagged Questions

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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### Why is the Moon considered the major cause of tides, even though it is weaker than the Sun?

You have likely read in books that tides are mainly caused by the Moon. When the Moon is high in the sky, it pulls the water on the Earth upward and a high-tide happens. There is some similar effect ...
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### Impulse and force in a karate chop, can we maximize force minimizing the time of impact?

I have heard that we can maximize the force by minimizing the time of impact in a punch. If that is true, the paradox is if we increase the time of contact with the same amount of force still we ...
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### Validity of work-energy theorem in presence of non-conservative forces?

How can the work-energy theorem be valid in presence of non-conservative forces since conservation of energy is not there?
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### What forces are at work in a loose ball bearing bicycle hub?

I've landed in a physics debate amongst bike mechanics. In a typical bicycle hub you have a simple bearing; the cups are set in the hub, the race (cone) threads onto the axel and there are just loose ...
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### Elasticity of a body on which variable force is applied

Let us consider a rod of some cross sectional area $A$ and length $L$. At one end a longitudinal foce of 5x acts on the rod. At a distance of $\frac{L}{2}$ from that point longitudinal force of 5x ...
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### How are the half life of particles mathematically related to the inverse square laws?

This video https://www.youtube.com/watch?v=K6i-qE8AigE&list=PL3B0924C6A0CB8B67 explains how forces are boson particles. It talks about the other non-force particles giving off and creating bosons, ...
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### Why liquids in hydrostatic equilibrium stay at the same height? (open tubes)

This part of the book says that, because the two liquids have the same pressure at the same height (that's true), then if a liquid has a higher height, the liquid would have more pressure at a ...
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### Will the usage of Exo-Skeleton Gear actually weaken the human body over time? [closed]

As we all know, Exo Skeletons as they exist now are just a series of Force multiplying apparatuses working together, also the human body changes to accommodate environment specific factors in order to ...
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### Why do Signs Fall?

My question in this post is, why do signs with large angles fall? For example, fold a piece of paper in half, set the angle between the two halves, and place it on the floor; it will stand or collapse ...
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### How does one figure out how fast water is moving through a water intake on a dam?

Say the dam is Hoover dam for example. The intake is where the water flows in to turn the turbines that generate electricity. I want to know if there is an equation that describes the speed of the ...
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### A model that unifies the strong, EM, weak and gravity forces?

Does there exist such a model that explains the force clusters (their origin, relations between them): the strong, EM, weak and gravity forces?
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### Why does iron sink in molten iron instead of floating?

Why does iron sink in molten iron whereas ice floats on water? Both are solid states of their own form, so why is one floating and the other sinking?
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### Work in electric potential

I've read that if we want to move a charge in an electric field then we need a work of an external force to move it from a low potential energy to a high one , but then I read on another source that ...
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### Rate of acceleration for two hanging masses in two experiments

I conducted an experiment where two masses of different weight were attached by a string and fed through a pulley. The difference between the masses was $0.025\: \mathrm{kg}$. The lighter mass was ...
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### How does the Lorentz force work?

How does the Lorentz force work? In the context of a homopolar motor. I am a year 13 student so please keep your answers simple! I am having trouble understanding the Lorentz force; does the magnetic ...
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### How is potential energy actually stored in a steel spring at the atomic level?

Elasticity is one the most intriguing phenomena, wiki gives a summary explanation of what happens in a steel spring: the atomic lattice changes size and shape when forces are applied (energy is ...
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### What are fundamental dimensions used to describe the physical universe? [closed]

I have heard that the universe can be explained in terms of the four fundamental forces. I have also heard it can be explained in terms such as space, time, energy, mass or even motion. To further ...
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### Who plays the role of centrifugal force in an inertial frame of reference?

It is noteworthy to quote a sentence from my book, It is a misconception among the beginners that centrifugal force acts on a particle in order to make the particle go on a circle. Centrifugal ...
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### Physics Forces and Friction [closed]

I'm working on this problem for my college physics class. It has to do with forces and friction and I want to make sure I go about this problem in the right way. I believe my teacher said that this is ...
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### Why do you have less control over a bicycle with a broader steer?

I recently had an argument with someone on why a bicycle with a broader steer gives you more control. We both had different answers to this question and neither could convince the other. First a ...
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### How to find “Time” from “Force vs. Velocity” graph? [closed]

If I have Velocity on the $y$ axis and force on the $x$ axis how can I calculate the total time it takes to reach 4000 newtons? Is this just a case of integrating the gradient of the line?
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### Finding Acceleration of Two Masses in an Ideal Pulley [closed]

I am stuck on this problem: Two masses are connected by a string which goes over an ideal pulley. Block A has a mass of 5kg and can slide along a rough plane inclined 30 degrees to the horizontal. ...
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### Where does the force to stop a constant velocity object come from?

If a ball hits a wall at a constant velocity, it will slow down and eventually come to rest. Since the ball was at constant velocity, it was not accelerating, and so there was no force. Also, the ...
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### Force and Energy in robots

There are two similar and hypothetical robots that move with wheels powered by motors, Robot A and Robot B. Robot A has a gear ratio of 3:1 (The gear connected to the motor is three times larger than ...
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### Could Galileo ever prove that $g$ is the same for a feather and a hammer?

Do you think he could have possibly found a way to make a feather and a hammer touch ground simultaneously, as they should, according to gravity? Can you make up a device that avoids air resistance? ...
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### How would the Sun's gravity affect us if we weren't in orbit?

So since we're in orbit around the sun, we are basically in free-fall. From what I understand, this means that we don't feel the gravity of the Sun like we do the Earth. Just like astronauts on the ...