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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162 views

Question about Torque Reaction of a Helicopter

This image below about the torque reaction of a helicopter has confused me a bit. I would like to ask whether i understand the principles here correctly. In the picture we see a helicopter whose main ...
3
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2answers
716 views

Estimate for energy dissipated by a damper/dashpot

I have a system with a mass $m$ attached to the end of a cable. The cable mass is assumed negligible. The cable is attached to the ground at the one end while the other, with the attached mass $m$, ...
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1answer
216 views

rotation behavior of spinning discs

If two discs of equal mass and volume are parallel to each other but not touching, share an axle but using magnetics do not touch it, are not under gravity, and begin to rotate in opposite directions ...
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1answer
95 views

What is meant by saying the work done by a conservative force is -(change in PE)?

I read through all related questions, and they are almost the same, but I still didn't understand this and so am asking again. What is meant when we say that the work done by conservative force is = -...
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0answers
61 views

Third law of motion when action and reaction are separated by some time

For every action there is an equal and opposite reaction. I have used this law only when bodies are in contact with each other which means for every action reaction is produced at same instant of time....
3
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1answer
168 views

Does a rotating object have more inertia, mass and gravitational pull?

When an object is rotating on an axis, it has stored rotational energy in it. Since energy and mass are related, does this stored rotation increase the mass of the object? And if so, will it be harder ...
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2answers
162 views

How force is transferred from one body to another

If there are 3 coins , namely 1 , 2 and 3 as in figure. When coin $1$ strike coin $2$ ,the coin $2$ passes the force to coin $3$ and the coin $3$ moves away. Case :1 How does this happen? What ...
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1answer
230 views

Force on side of pool from water

Given a pool with dimensions $$\ell \times w \times h \, ,$$ I am trying to derive an equation that will yield the force by the water on the sides of the pool, namely $$\ell\times h \quad \mathrm{or} \...
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4answers
213 views

Why is force called the rate of change of momentum? [closed]

Why is force called the rate of change of momentum? If I push a wall I do exert a force but there is no movement; so is there force acting on the wall?
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1answer
30 views

Circular Banked Track Normal [closed]

I don't understand the phrase 'the total pressure exerted by the car on the track is normal to the plane of the track.' Is the pressure the weight of the car, so does the normal = mg? I have tried ...
1
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1answer
245 views

How charges can be at rest if there is a force on it?

Electrostatics deals with forces between charges at rest. But if there is a force on a charge, how can it be at rest? My guess is that charges is being kept at rest by some unspecified forces that ...
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1answer
198 views

Negative Sign in Compression Modulus

I noticed that the bulk modulus often has a negative sign appended to it in order to cancel with a negative change in an object's volume; this allows the bulk modulus to be positive. However, I ...
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3answers
91 views

Instantaneous cause [closed]

The position of an object has a rate of change called velocity. The velocity of an object has a rate of change called acceleration. Force applied is proportional to the acceleration of the body (...
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0answers
91 views

Derivation Electric force

I’m a physics of high school (SMAN 3 Bandar Lampung, Lampung, Indonesia 35116). I make the experimental apparatus in static electric field. Instrument arrangement in the image below: The theoretical ...
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2answers
88 views

What are the most efficient ways to transmit force through air? [closed]

I am taking part in a robotics competition, where the challenge is to create a pair of robots which successfully navigate a series of obstacles. However, the rules state that of the two robots, only ...
1
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0answers
59 views

Friction of an object falling between two walls

I'm simplifying this problem into 2D for easier understanding. Lets say we have 2 vertical walls separated by distance x. Inside these walls I place an object that is only slightly smaller than x in ...
1
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1answer
291 views

Repulsive Force between two Electromagnets

This question might seem a bit too basic(or advanced!), but it is the one to which I'm really desperate to find a simple enough explanation and solution. Ok, So here's the problem, I have two ...
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1answer
229 views

Physics pulley problem [closed]

A 64-kg housepainter stands on a 14-kg aluminum platform. The platform is attached to a rope that passes through an overhead pulley, which allows the painter to raise herself and the platform. (Ignore ...
3
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1answer
91 views

Pushing an object in orbit outwards

I wonder what would happen if an object in orbit were to be pushed outwards. I can imagine 2 outcomes: either it would keep spinning outwards away from whatever it is orbiting at a finite speed ...
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0answers
56 views

Does Light have Weight?

If I light a torch and hold it against a wall, will the wall feel any force? If yes, what factors does the magnitude of such a force depend upon? (Area of the wall covered by the beam, intensity of ...
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2answers
1k views

Which travels further, a football or a soccer ball, when thrown?

I recently answered this question: Laminar Versus Turbulent Flow and it caused me to think of the following situation. Given that an (American) football weighs between Football 400 to 430 grams, and ...
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0answers
111 views

are 2 parallel magnets stronger than 1?

if I have 2 parallel magnets of neodymiun the force of them woul affect in the same as just one or increase? I have heard that the force would be the same and the only difference in that case is that ...
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2answers
737 views

Can a pilot in a small spaceship feel G force in space?

I am not really good in physics so I might be wrong at some points, but here is the situation. Consider a spaceship of the size of a fighter plane. And like a fighter plane, the ship is very mobile. ...
2
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1answer
46 views

Does every force which seems to have no effect cause a deformation?

The example in our discussion was: If I glue a peanut to the ceiling, does the ceiling bend? Some people argued that it wouldn't because ceilings do not bend for peanuts. Some people argued that the ...
4
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1answer
94 views

Why does ice fall from the top of the ice tray first?

I haven't found an answer for this anywhere, so hopefully this community can help. It's not important at all that I know this but I'm curious. If you take a plastic tray of ice from the freezer and ...
1
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1answer
711 views

How is the fall time for a parachute affected by the mass of the load?

Why do parachutes with a heavier load fall faster than a parachute with a lighter load?
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1answer
54 views

Reaction force explanation? [closed]

I heard that reaction force is the total force applied back due to electromagnetic repulsion between the atoms of the thing that exerted the force and the thing that the force was exerted on, so can ...
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2answers
111 views

Gravitational force acting on two particles

According to Newton's Laws of Gravitation, $F=Gm_1 m_2/r^2$ So gravitational force F is directly proportional to $1/r^2$. Now if we consider 2 point masses in vacuum at rest at a distance 'd' apart,...
2
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1answer
66 views

Does Hooke's Law apply for microscopic amounts of compression?

I would like to set up a simple laser interferometer to measure the compression of a material experiencing forces around $8 \times 10^{-4}$ N. But I need to find the spring constant to calculate the ...
8
votes
4answers
445 views

Is work done by a pseudo force?

If a body is viewed from the frame of another body which is itself accelerating, will work be done by the pseudo force acting on the first body in the frame of second body ( provided the first body is ...
0
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1answer
62 views

Formula connecting Force and Power

Is there such formula? There probably is of course, but i would like a very concise description of how to derive it, in order to better understand myself. Thank you in advance.
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0answers
37 views

Diamagnetic Sphere Moving through Solenoid

I've seen the videos of frogs being levitated due to diamagnetism. What happens if the frog (or another diamagnetic object) enters a solenoid with an initial velocity? Specifically, consider a ...
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2answers
89 views

Does the frame of reference change the behavior of a particle

"Behavior" word in the title is not very correct. I'm in a train at a railway station and on the platform there is a glass case (the mass of case is 5 kg and if it gets hit with a velocity of 10 N ...
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1answer
202 views

Calculating output forces of bicycle wheels

Based on the force on the rear gear $F_t$ and the radii of the rear gear $R_g$ and rear wheel $R_w$ , how would you calculate the force the bicycle exerts on the ground when it is accelerating? I ...
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1answer
200 views

Calculate Spring Constant [closed]

I am editing the question because it was misunderstood to be a homeowrk question. I am modeling a Stumps equipment for a game called Cricket.Typically the game consists of 3 wooden stumps ...
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2answers
213 views

Why does the superposition principle work in method of images?

Okay, let there be a conducting sphere having radius $a$ initially charged with $Q$ & insulated. Now, $q$ is brought in front of the conductor at $y$ from the center. Now, Jackson in his book ...
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3answers
539 views

Horizontal and vertical acceleration of a ball on a slope?

I understand that you resolve the components of the balls weight parallel and perpendicular to the slope in order to calculate the force due to gravity that actually acts down the slope. The ...
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2answers
57 views

Pertaining to Newton's laws, how do so many objects acheive perfect equilibrium?

Suppose a light is hanging from a ceiling. Supposedly, the force of tension pulling it up is exactly the same as the force of gravity pulling it down. Why is it that the tension happens to be exactly ...
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2answers
98 views

Why does the ground always push up?

In the example of a bouncy ball being thrown at the ground, at some angle from the normal, $\theta$, we know that the ground will apply a force in the normal direction, causing the ball to rebound at $...
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0answers
58 views

Is it wrong to equate the net force to the force by the spring to find its maximum expansion?

In the picture displayed here , I have two blocks of masses m1 and m2. They are connected by a spring and a leftward force is applied on the block of mass m1.This will , ofcourse , result in expansion ...
0
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1answer
143 views

Why is it effectively impossible to balance this rectangle block on a triangle block? (See photo)

I've always wondered why it's basically impossible to balance a rectangle block on top of a triangle one like this. This is my nine-year-old giving it a try. I have never in my life gotten it to ...
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2answers
96 views

How does friction act on a body, if only 2 regions on it are rough? [closed]

While tackling an Olympiad question, it came to my mind that friction need not act in the same direction at all points on a body. I thought of using integration to evaluate the net frictional force, ...
1
vote
2answers
112 views

Why is sometimes more difficult to lift a baby?

I have a small cousin and she enjoys when I pick her up, which I can do pretty easily. Sometimes though she decides she wants to make my life difficult, and when she decides so, she tells me she is "...
0
votes
4answers
565 views

Why Do Objects move?

Let's imagine a block resting on horizontal table. When We apply a force which is greater than frictional force it moves. But why does this happen? Why can't friction withstand any force? As we know ...
1
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1answer
58 views

Extension spring and permanent damage

Is there a way to calculate how far an extension spring can be extended before it suffers permanent damage? There are some online calculators, but how are they done? This calculator is the most ...
0
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1answer
161 views

Moments and forces, when part of the scenario involves a circle or arc rather than a straight line

Some questions below, involving strategies, regarding the following problem: A hoop of weight $20$ Newtons can rotate freely about a pin fixed in a wall. A string has one end attached to a pin, ...
2
votes
1answer
36 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 ...
3
votes
4answers
377 views

Is there difference in force when the height increases?

Consider a man with mass 50kg. When he jumps from a 2 meter height, the total force is $F=ma$ ie (mass * gravity), but nothing happens to him. When he jumps from a 50 meter height, the total force ...
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2answers
609 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 qualifies....
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2answers
336 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?