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
1k views

Weight versus gravitational force [duplicate]

What is the difference between weight and gravitational force? I am a beginner who want to study physics properly.
2
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0answers
220 views

Odd experiment results (electromagnetics)

Okay, a bit of background. So I'm working on a linear accelerator (you might know it as a Gauss rifle), and I had worked through the equations I thought I needed (Magnetic force, displacement, etc.) ...
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2answers
301 views

Why did I get this dynamics question wrong? [closed]

I'm wondering as to why I got this physics question wrong, despite it being quite simple in nature. I believe that I missed something while working on the problem. Basically, the question involves ...
2
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2answers
460 views

Nature of tension in a massless rope [duplicate]

I'm faced with a conceptual problem, where I am supposed to describe the motions of the following system (two masses on each end of a totally inelastic rope hanged on a pulley): I understand that ...
3
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1answer
191 views

Confusion with Newton's Second Law : Position & Time Dependence of Force

For a conservative force $\vec{F}(x,y)$ we have $$\vec{F}(x,y) = - \vec{\nabla}\phi(x,y)$$ where $\phi(x,y)$ is a potential function for $\vec{F}(x,y)$. Again, Newton's second law states that $$ \...
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1answer
362 views

How does the weight of the pendulum's bob cause a torque?

I know that a force will cause a torque if the force has a perpendicular component to the distance from the pivot point. However, in the figure above, I can't seem to visualize how the weight of this ...
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2answers
957 views

Why does a Ball bounce back if Forces are Equal and Opposite?

When a ball is thrown onto a wall, the ball exerts a force onto the wall. According to Newton's Third Law, the wall will exert an equal and opposite force to the ball. Thus, how would the ball be able ...
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1answer
504 views

Centripetal force in loop motion

I saw it from the book which talk about centripetal force in circular motion The main idea here is the balance in the term of relation between velocity and centripetal acceleration - centripetal ...
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3answers
3k views

Drag force on a flat plate

The solution for this apparently is $\frac{1}{2}C \rho A V^{2}$ where $C$ is the drag coefficient, $A$ is the area and $\rho$ and $V$ are the wind density and velocity. Let's do it without the drag ...
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1answer
124 views

Fictitious forces and $\omega$

I have been studying fictitious forces, such as the centrifugal force and Coriolis force. The equation for the centrifugal force is given by: $$F_{centrifugal}=-m\omega\times(\omega\times r)$$ My ...
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1answer
35 views

Various springs acting on a point mass

The force exerted on one spring is $\vec{F}=-k\vec{r}$. Now suppose we have N slinkys with stiffness $k_1,k_2,k_3,...,k_N$ where they have one end tied to fixed points in space with coordinates $R_1,...
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2answers
2k views

Newton's Third Law Exceptions?

Lately I've been brushing up on some of my old Physics texts from college. Most recently, I've been rereading parts of "Classical Dynamics of Particles and Systems (5th ed.)" by Thornton and Marion. ...
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3answers
317 views

Joules to do something

If my very limited understanding is correct, then, not accounting for gravity: 1 Newton can move 1 kilogram 1m But, can 2 Newtons move 1 kilogram 2 meters? Is this because 1 Newton = acceleration ...
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1answer
54 views

Joules To Move A Kilogram In Space [closed]

If roughly ten joules lifts one kg on earth one meter, how many in space? Meter / joule/kilogram Kilogram/meter/joule
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1answer
256 views

Does magnitude of a charge influence magnitude of force that individual charge exerts on another charge [closed]

two point charges, q1 and q2, are placed 0.3m apart on the x-axis, as shown in the figure above. Charge q1 has a value of -3 nano Coulomb and q2 has a value of +4.8 x10^-8 C. The net electric field at ...
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1answer
138 views

What happens to the gas in the container in this picture when the container is tilted

So the test question asked what would happen to the gas if this container were tilted on its side. The piston shown here is 10 kg and moves frictionlessly. I said that the pressure inside the ...
0
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1answer
244 views

How to convert translational energy to rotational energy [closed]

Suppose that I have a body moving at certain velocity in straight line. So it has translational energy. I want to convert this energy to rotational energy of another body, by making the velocity of ...
2
votes
2answers
108 views

Estimating the force needed to increase height of a mountain?

How would you estimate the force required by a tectonic plate to make the height of a mountain increase when it pushes against another? I've used a method to try and do it for Mt Everest and have ...
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3answers
198 views

Distinction between torque and force

Distinction between Torque and Force. Consider a case when a cylinder is rolling down a rough inclined plane. While analysing its motion, we consider the force applied by the friction and the ...
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1answer
488 views

Accelerated wedge [closed]

Consider the following figure, where a mass $m$ is placed on a wedge which is accelerated to the right ($\vec a$) which could be negative. The coefficient of friction between the mass and the wedge ...
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3answers
939 views

Direction of friction force between two boxes

There are two boxes on top of each other. The bottom box is dragged right by a constant force. What is the direction of friction of the top box against the bottom box?
5
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2answers
2k views

Is a chain REALLY only as strong as its weakest link

I heard this quote a lot (especially from my teachers) and I always wanted to know whether or not it was actually true. I think that its partially true; a chain with one weak link is weaker than a ...
0
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0answers
53 views

What is “W external” and “W internal” in Energy conservation law?

When I solve the energy conservation problem, I am confused when I have to make the term positive or negative. For example, someone throws a ball right up to the ground with velocity, $v$. The ball ...
0
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0answers
145 views

How strong is the force of space expansion?

There are many questions about space expansion, its cause, or its effects. But I have the feeling we never get straight and simple answers. I do not expect answers to be simple in general, but I ...
2
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3answers
909 views

The effect of windspeed on a car

I've worked problems in the past in trig class concerning the effect of wind on the speed of a plane and it's flight path and was wondering if a similar thing occurs with a car. First off, I'm ...
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2answers
129 views

Does Centripetal Force Change Direction?

I have been struggling with this question that I have, "Does centripetal force change direction?" From every point, it points to the center. But if we draw its vector, we draw the tails from ...
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1answer
52 views

Modeling wall's behaviour

Sorry if the quesiton is inconvenient, but I judged the physics forum would be the best place to go. My house is divided in two parts by a wall, and there's some tree pushing it, so the wall is about ...
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7answers
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 ...
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2answers
189 views

What will happen in principle if one tries to push a neutron star?

When we push an object it moves due to the mutual repulsion between the electrons in our hand and the electrons in that object. Since a neutron star contains only neutrons, what will happen in ...
3
votes
2answers
657 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 ...
2
votes
1answer
1k views

Finding the acceleration given only an angle

This is one of my homework problems for a College Physics I course: Dana has a sports medal suspended by a long ribbon from her rearview mirror. As she accelerates onto the highway, she notices ...
0
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1answer
131 views

The forces acting on 2 boxes [closed]

Consider the following figure: The surface is not friction-less. When the force $F$ is applied on mass A: Is the force the mass A applies on mass B larger, smaller or equal then the Force that B ...
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1answer
218 views

How to explain centrifugal force from frame of reference of Earth?

Suppose we have a circular table. We have made a straight line groove in the table extending from the center to the circumference. Now we place a block at some distance from the center in the groove ...
2
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4answers
2k views

If a truck collides with a car, can the truck experience a larger force?

I am confused, here is a question: A large truck and a mini bus both have same velocity V and they collide and stop. The collision lasts for 1 second. A) Which one of the two will experience ...
0
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0answers
193 views

Why is area considered and not volume to find the force of a solenoid?

I am doing a project involving solenoids. I found multiple websites that say the force (in N) a solenoid exerts on a soft iron bar as it enters the coils can be given by the equation $$F=(NI)^2\mu_0A/...
3
votes
2answers
167 views

Wasted energy applying a torque

In another question I asked how find a way to deduce wasted energy, but I did not get a satisfactory answer. I have changed the setting here which brings us more close to the solution. Instead of a ...
0
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2answers
462 views

What is a conservative force?

Currently I have three different pictures to describe/understand conservative forces. For the moment I just want to get an electron from point A to point B. In the near surrounding is another electron ...
1
vote
1answer
976 views

Advanced kinematics problem regarding $F = ma$ [closed]

I really need help with this problem. Thank you for your time. Question: Look at the figure below. Derive the formula for the magnitude of the force F⃗ exerted on the large block (mC) in the ...
5
votes
1answer
235 views

How fast until you feel wind in space? [duplicate]

I couldn't find this question asked anywhere else, so I thought I would ask it here: does anyone know how fast you would have to be traveling in space to feel 'wind' from the particles in front of you?...
3
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2answers
4k views

“Magic” Speed to Drive Over a Speed Bump: Myth or Reality?

A somewhat controversial aspect of speed bumps (sleeping policemen for those in the UK) is that they arguably cause more loss of life than they prevent by acting as a hindrance to emergency response ...
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2answers
37 views

Possiblity of predicting behavior of system when properties described as functions over space?

Suppose I am given a system that consists of a distribution of charged particles(which are all over space and are point-charges). They are described by a set of functions instead of variables. These ...
2
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3answers
3k views

Can you punch a hole in an A4 sheet of paper with your hand?

The heading says it all, but let me explain it a little further. Suppose you hang a sheet of paper (A4 size) from one end leaving the other end free. Now practically it seems impossible to punch a ...
7
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2answers
5k views

Can a bullet shot through a glass make a clean hole?

One can often see (hopefully only in the movies) that a bullet shot through a pane of window glass leaves a hole in it, but overall the glass is left largely intact. However, a low-speed projectile, e....
0
votes
1answer
57 views

Gravitiation force of a sphere

Was wondering about Shell Theorem, specifically about the immediate results. Force (on a point mass) inside a shell is 0. Force (on a point mass) outside a shell is GmM/r^2 From what i know the ...
1
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1answer
798 views

Thrust measured in grams and discerning horizontal acceleration?

So, I have a small ducted fan which has a listed "thrust" of 75 g at a set voltage. I'm going to assume the "g" is short for "grams". Why would this be measured in grams instead of newtons and how ...
2
votes
1answer
689 views

Static and kinetic friction [closed]

Say you have block1 on top of block 2 and the whole system is accelerating toward the right at a certain acceleration. Due to inertia block 1 wants to move backward to the left so there has to be a ...
1
vote
1answer
77 views

General potential of rotating system

I'm new here at the physics site, and not really that deep into the area of which i'm going to ask a question about now. Therefore please feel free to ask clarifying questions. I'm trying to deal ...
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1answer
56 views

Vectors and Forces problem [closed]

I have a question that I think I have an idea of how to answer but I am unsure can someone please verify for me? Here goes: Here is a box and a force (vector say, F1) of 10 N in the positive ...
0
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1answer
7k views

Maximum length stretch of vertical spring with a mass? [closed]

Having a vertical spring, if we hang a mass to it, what is the maximum stretch length of spring? and how big should be mass to break the spring?
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1answer
227 views

Electromagnet force equation clarification

So, from a previous previous question, I know what plane the force from an electromagnet will affect a ferromagnetic material in. I thought that would be enough, but working through some problems ...