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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1answer
106 views

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 ...
5
votes
2answers
10k views

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 ...
1
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2answers
38 views

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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2answers
31 views

Does displacement affect force? [on hold]

We conducted an experiment about work on lifting objects of different masses. Each object was lifted to 50 cm and then 100 cm. The force did not change. Is this supposed to be correct? What is the ...
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0answers
11 views

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 ...
2
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4answers
290 views

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 ...
2
votes
1answer
123 views

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 ...
3
votes
2answers
127 views

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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4answers
288 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 & ...
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0answers
12 views

Movement of a bobbin thread when pulling it's thread at certain angles [on hold]

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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0answers
37 views

All about Frictions. (Help me) [on hold]

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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0answers
17 views

Pseudo/Fictitious force [on hold]

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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1answer
63 views

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, ...
1
vote
1answer
83 views

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 ...
2
votes
2answers
180 views

Effect of position on a motorbike turning

While searching tips for driving a motorbike on wet roads safely, I heard some pilots saying to lean inside the slope makes the bike less tilted, so it's safer. I agree leaning make the bike less ...
2
votes
2answers
43 views

Why is $mg$ positive and $N$ negative in this problem?

In this problem: A car of mass $430\ \mathrm{kg}$ travels around a flat, circular race track of radius $178\ \mathrm{m}$. The coefficient of static friction between the wheels and the track is $0....
2
votes
2answers
63 views

Why would a moving infinite region of magnetic field exert an electric force?

I'm confused about the Lorentz force in relation to the frame of reference. There are many questions about that here, but I still don't get it. I've tried to break it down to the most basic example. ...
-1
votes
3answers
727 views

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 ...
0
votes
2answers
29 views

Pressure in deodorant can

Pressure in a deodorant can is greater than the surrounding pressure but still the can is in equilibrium with the surrounding . Why does this happen. If we apply $F = PA$ then $P_{in}A= P_{atm}A$ and ...
-4
votes
0answers
52 views

Pulling and pushing two objects through a rigid member in between the objects [closed]

Problem statement: I have two objects of mass $m$ placed at some distance and connected each other in-between with a rigid member which can take compression or tension. Through a point on rigid member ...
0
votes
4answers
296 views

Work and free body diagrams

I am a bit confused with how to find work when there is a free body diagram. I am trying to work out this problem, and in it a box is being pulled at a constant speed by a rope at a constant angle ...
1
vote
1answer
229 views

Why golf balls travel faster if they spin?

From the book I have been given to read I found that balls spin due to the centripetal force but i am confused about how exactly do the resultant force causes it to spin and move forward about the ...
0
votes
2answers
64 views

Frictional force on an inclined plane with applied force = Mgsinx - Mgcos x?

I was reading Introduction to Classical Mechanics (Morin) recently and came across this example, which said that the friction force (marked $F_f$) is $Mg\sin\theta - Mg\cos\theta$. However, I can't ...
0
votes
2answers
81 views

Proving that force satisfies the laws of vector addition [duplicate]

A vector quantity has both magnitude and direction. So, for any physical quantity to be a vector, it should have a direction and a magnitude. Though this is a necessary condition for any quantity to ...
10
votes
2answers
214 views

Charged Accelerometer in Orbit

It is well known that an accelerometer (or any other object for that matter) in a gravitational orbit will register nearly zero acceleration. According to this answer, this is because the object is, ...
0
votes
1answer
85 views

How is the Dirac delta function used in classical mechanics? [closed]

If the contact force applied to a physical object (ex. empty bucket) is given by the Heaviside function: $$ F(t) = F_0~H(t)=\begin{cases} 0, t<0 \\ F_0, t \geq 0\\ \end{cases} $$ Then,...
2
votes
1answer
195 views

In perfect vacuum (no external force), if I apply a small amount of force to a body, will it continue to accelerate forever?

According to the equation $F = ma$, the greater the force applied to a body, the greater its acceleration. But in a place where there is no gravity or any other kind of external force, if I apply a ...
3
votes
7answers
7k views

If the earth has gravity, why don't we all collapse to the center?

I'm sorry if the answer is obvious for you guys, but why don't we all (including buildings, road, people, the ground) collapse to the center of the earth because of gravity? Is it because we have ...
6
votes
1answer
285 views

Force problem related to adhesive and bonding

I have two PCBs (printed circuit board), and they are glued by adhesives, as show in the pictures. And the location of the adhesives are indicated on the picture (please notice that NO adhesive is ...
0
votes
2answers
186 views

Resultant force on the side of a tank of water

A closed tank rectangular in plan with vertical sides is 1.8m deep and contains water to a depth of 1.2m. Air is pumped into the space above the water until the air pressure is 35kN/m2. If the ...
2
votes
8answers
13k views

Trouble understanding the concept of true and apparent weight

I need help understanding the concept of true weight vs apparent weight. I understand this much: if someone is standing in an elevator on a scale, the further up they go the less the reading on the ...
-6
votes
0answers
35 views

Why does the universe allow matter to bend it and if there was too much matter could it rip time? [closed]

I'm not a person that Knows a lot about space but I am interested to see what awnsers I get my hands on. Especially about space and mass, how it functions so well with mass its a very interesting ...
0
votes
2answers
663 views

Tension in string and gravitational force on bob relative strength

When calculating time period of simple pendulum (an approximation of SHM at small amplitudes) we take gravitational force greater than tension in string and resolve gravitational force in two ...
1
vote
1answer
41 views

Can we know the tension of the string that is connected to a pully?

If the pulley have mass, I learned that T1 and T2 isn't same. then what about the circled part of the string? can we calculate the tension with given T1 and T2?
1
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2answers
1k views

Can we define tension in a string as the reactive force produced in a string being pulled at both ends?

In my textbook, the definition of tension was given that Tension is the reactive force which exists when string is being stretched at its both end. After it there was a case given that to calculate ...
4
votes
6answers
6k views

Force required to drive car

From what I know of Newtonian Mechanics, if an object is moving at a constant velocity, the net force acting on that object is equal to zero. If there is friction, then the applied force required to ...
-3
votes
1answer
33 views

Calculating horizontal and vertical components of force [closed]

4a) Calculate the horizontal component A and the vertical component B of: i) a 6.0N force at 40 degrees to the vertical I'm not sure about this but would this be the way to calculate it? $$6\sin(...
0
votes
2answers
44 views

About a particle suspended by a string, moving around in a circle

The question I'm trying to answer is this: I'm having difficulty with understanding this part of the soloution: I understand how a formula for $v$, the velocity of the particle, was derived, but ...
1
vote
3answers
75 views

Conceptual doubt in Tension force

I recently studied that Tension in a string is a kind of force originated from electrostatic attraction between the atoms of the string in which the force is originating. My doubt was that: Assume ...
4
votes
1answer
265 views

Force field for calcium ions, potassium ions and water in molecular dynamics

I want to adapt my existing MD simulation so that it can handle these three species. For the interactions of the ions I thought that I would use the coulomb potential, but I don't know what sort of ...
0
votes
2answers
65 views

Minimum force needed to keep the book from slipping?

I would just like to know if my answer to part C is correct because I am confident in parts a and b, Also note that 51.5N is the wrong value for P. P=515N. Ok so since P= normal force, this means ...
0
votes
3answers
246 views

In what direction does the friction force point? [closed]

I'm really confused about the direction of friction force. I think about collision of two balls and think that "friction force is opposite to the relative speed of the contact point of the two ...
0
votes
1answer
25 views

Rocket Propulsion Equation: Meaning of Net Force

Upon deriving the rocket equation, my textbook (Giancoli) states that the meaning of the net force on the final equation is the net force on M. Note that $M$ and $dM$ are used as the rocket (without ...
1
vote
1answer
181 views

Why does thawing Coca-Cola generate force and expand the can as it thaws?

If I take a warm unopened aluminum can of Coca-Cola and place it in the freezer and let the Coca-Cola freeze solid, then take the can out of the freezer and let it thaw unopened in a typical room, the ...
-1
votes
5answers
142 views

Measuring force of a punch

I'm trying to build a device that can mesure the force of a punch. ​ My initial plan was to build a platform with 4 springs (one at each corner) and an accelerometer in the middle. But, if the ...
3
votes
0answers
36 views

How do force carrying particles “give” force? [duplicate]

So, I am not taking physics in school, but I do have an interest in it, and I was wondering, in the standard model, all of the force carrying particles (photons, Z Bosons, W Bosons, gluons, and (...
0
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0answers
17 views

The “force” of gravity is an illusion: things follow geodesics in space-time warped by mass-energy - can other forces be explained by similar models? [duplicate]

As I understand it, the force of gravity between two objects is not really a force, but appears to be so. It behaves in such a way that the Newtonian force explanation works in many cases, but the ...
0
votes
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 ...
0
votes
0answers
26 views

In d'Alembert's principle, how that the Reverse effective force and Force of constraints are different?

In d'Alembert's principle, how that the Reverse effective force and Force of constraints are different? Both are opposition or restriction on the body but how both be different in real?
-1
votes
1answer
38 views

A silly, but confusing, question about the Inertia coeficient of second law and inertial mass

My question is about the inertia coefficient on second law. To be more specific I have doubts on the notation. 1) Some authors show that the force $F$ is proportional to mass $m$ times acceleration $...