# 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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### Newton's Second Law Confusion

I don't quite understand the relationship between an object's mass, acceleration and net force. For example, if a car was going to the right at a constant velocity or with no acceleration, does that ...
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### Force and dimension is the same? [on hold]

I read somewhere that maybe we have 10 dimensions. We know that we have four dimensions (3 dimensions of space plus one of time). There are also four forces: gravity, electromagnetism, the strong ...
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### How to calculate impulse force of body hitting water?

I'm calculating the force of a body hitting water from a high height. So far I've figured out the velocity at the time of collisions would be 40 m/s. The body is 78 kg. I seem to need the time it ...
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### Few questions related to Tension

I am struggling with the concept of tension in a rope. Below specific questions. I am understanding tension to be an elastic force between rope molecules. If so, is it fair to say the net tension ...
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### What happens to forces when a charge travels at near c?

Suppose 3 electrons are travelling at $c - 1$mm at 1 cm distance The charges are at rest relative to one another in their frame, but what happens to fundamental forces Fe and Fg? What Fe does A get ...
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### Force dependence on velocity : Drag

I just listened to the second lecture of Leonard Susskind on classical mechanics where he discussed that force can't be proportional to velocity, since it's unable to retro-dict (predict past). He ...
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### Rate at which a pendulum bob slows due to air resistance?

I know that "perfect" pendulums would be able to swing forever, unperturbed by air resistance. However, since there is air resistance around us, pendulums (swinging bobs) slow down and move closer and ...
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### Does displacement affect force? [on hold]

I am sorry for being unclear with my previous question. The main topic of the experiment we conducted was about work. As we learned: $W = Fd$ Work, from my understanding, is the product of work and ...
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### Force on border exerted by a liquid

Why is it nearly universally understood that force in a liquid against a border is dependent on internal pressure, depth only, rather than weight of the liquid? Thus, for example, that the force from ...
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### What really is force? [duplicate]

I know the second law of Newton says $F=ma$ which seems to me the most fundamental expression of the force. In other words, force cannot exist without a "forced" one. It is somehow a "secondary" being,...
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### Problem in constraint equations

In this, if I want the acceleration constraint between $M$ and $2M$, I write $AM+2AB$=LENGTH OF STRING, which on differentiating twice gives $a_{m}=2a_{2m}$(which turns out to be correct). However, if ...
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### Understanding tension

I'm trying to understand tension. So here it goes: I'll start from the beginning. Let's assume I'm in space and can move around and apply forces. Let's say a rope is attached to a body(which is in ...
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### Work done by internal forces of a rigid body

I am reading Goldstein's Classical Mechanics book, and I came across that: In a rigid body the internal forces do no work Is this statement based on the assumption that the internal forces are ...
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### PVC Pipe ideal force [on hold]

A longbow is made with a string which is not stretchable and is made with a PVC pipe of radius of around 1 centimeter on the outer and 0.8cm on the inner radius. The pipe is 120 centimeters and the ...
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### Centripetal and centrifugal force

If a stone is rotated with the help of a rope, then both centripetal force and centrifugal force will be liberated. The magnitude of that forces are same, but direction of them are opposite to each ...
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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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### How can photons cause charges to attract? [duplicate]

Photons are the force carrier of the electromagnetic force. I do not see how this could result in a transfer of momentum that attracts objects together.
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### 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 & ...
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### Movement of a bobbin thread when pulling it's thread at certain angles [closed]

The problem: You try to move a bobbin thread by pulling it by it's thread. If you pull it while the thread is horizontal it slides your way but if it is at an angle the bobbin thread starts rolling ...
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### All about Frictions. (Help me) [closed]

A 20-kg body is on a plane inclined at 60° from the horizontal. The coefficient of friction is 0.22. What force at 30° with the plane will cause the body to move upward at a uniform speed? 2.A block ...
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### Pseudo/Fictitious force [closed]

A man is acclerating towards an object at rest. Accleration of the man is 2m/sec sq. , mass of the object is 2 Kg. What is the pseudo force on the object?
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### Wheel Sinkage Depth

I am trying to make a realistic car physics simulation for my game and the current thing that I am fighting to solve is rolling resistance. Although it's effect is minimal, this is important concept, ...
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### Validity of Point Mass Approximation in Newton's Laws of Motion

Chapter 2 of Kleppner & Kolenkow's An Introduction to Mechanics reads as follows - Newton's Laws describe the behavior of point masses. In the case where the size of the body is small ...