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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How to apply Newton's first law to moving object?

I'm new to many forces, such as gravity and friction, and I don't really know how they work. I'm trying to simulate a ball bouncing with a program, and it travels at a constant speed horizontally. I ...
5
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2answers
311 views

How does one write Newtons 2nd Law using the language of forms?

Newton's second law says that $F=ma$. Supposing that the force is conservative and can thus be expressed in terms of a potential $V$ we have that $F=-dV$. We have that $V$, being a function, can ...
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2answers
63 views

Why things wobble when submitted to wind?

If I place a little piece of paper in front of a fan, it is going to wobble/oscillate. Is it because the wind flow isn't constant ? Or because the air movement makes the piece of paper move away, so ...
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1answer
39 views

Net work done by projectiles?

When the projectile is in motion what is the net work done on projectiles? What i think? 0 first view: We know when we throw projectiles the initial KE and final KE is 0. So from work energy ...
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0answers
30 views

Force Between Two Solenoids

How does one calculate the magnetic force between two coaxial solenoids, placed in a way their currents are in the same sense? There is a simple way to treat both as dipoles and then calculate the ...
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2answers
75 views

A confusion regarding friction

Suppose there is a block which is being pulled by two forces A,B in opposite direction(as shown in figure). If we have no information regarding the forces $A$ and $B$, can we tell whether there is any ...
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1answer
58 views

What force decays an oscillating charge?

Consider this scenario: We have a charge on a spring. As it oscillates, it loses energy to radiation. What force decays the oscillation? As far as I can see, the only forces in the scenario are ...
2
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2answers
81 views

Why does locking the rear tires on a vehicle cause it to spin?

Handbrake Turns are often used in motor-sports and stunt driving to turn around tight corners. Essentially, the driver applies the handbrake as he enters the turn, in order to "kick out" the back end ...
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1answer
55 views

How does a skater moves by pushing sideways?

Take a look at this video http://www.youtube.com/watch?v=EmMf91AVUXc or take a look at the following screenshot. As you can see, the skater pushes almost perpendicular to the direction of movement ...
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3answers
118 views

Tension in a rope

In an ideal case, we assume strings and ropes to be massless and having same tension throughout. However, I was doing some questions which involved a rope with mass. The question was that if a ...
2
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2answers
69 views

Will the water go inside the moving water bottle?

Let's say that there is a empty bottle in the water moving at a high speed like this: My question is: Will the water go inside the the empty bottle when the bottle is moving at a high speed? If ...
1
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1answer
45 views

Condition for 2 bodies to move together

The condition for 2 (or more) bodies to move such that they are always in contact, is that their accelerations (and velocities) along their common normal should be same. Can someone explain why this ...
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0answers
33 views

irreversibility Aristoteles law of motion

I am watching the second lecture from the theoretical minimum and do not understand the argumentation of Susskind. For those who do not want to watch the video. It is about the law of motion from ...
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4answers
1k views

Will the sea form a concave surface?

Without neglecting the fact that the earth is rotating, let us be in a ship (such that there is no relative motion between sea and ship) in a sea that surrounds the northern most or southern most ...
1
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1answer
58 views

How exactly do walking canes and crutches help?

I am reading introductory physics, and there is a chapter on equilibrium. In the chapter, the author mentions how devices can exploit distribution of forces to help those that are physically ill, via ...
0
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1answer
49 views

Friction as a Non-conservative force

Intuitively, one can find friction to be a non-conservative force. How can one prove that it is non-conservative?
3
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1answer
43 views

How does stress change through a bar that sharply increases in diameter?

I am looking to analyse the stress through the following bar: The bar is of circular cross section, homogeneous in material, that is of a certain diameter on one half, and a large diameter on the ...
1
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3answers
47 views

Frictional forces apposing motion

Please could someone help with some physics about resistive forces that would slow a ball down which is rolling across a floor. I have found conflicting bits of information about the effect friction ...
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0answers
26 views

Does dimensionality determine the net effects of randomly oriented forces on an object?

My question relates to the orthogonality of random vectors in high dimensional space, and the relationship of random vectors as a function of dimensionality. My question can be formulated as a ...
0
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1answer
45 views

Force vs. Momentum [closed]

Obviously, if no external non-preservative force acts upon an object, if we apply a force to the object than the object will continue to hold that force within them. My question is, the object would ...
2
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7answers
560 views

Free fall into circular motion

If I'm on a roller coaster free falling from height $h$ and then suddenly start going into horizontal motion with a radius $r$ of turn what is the $g$-force I experience? I worked out the equation ...
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3answers
122 views

A misconception in an application of Newton's laws

When a body is kept in ground, and is at rest, the downward gravitational pull is balanced exactly by the Normal Reaction if we assume the earth to be an inertial frame. But this would mean that any ...
1
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3answers
80 views

Calculate acceleration from power [closed]

I am currently programming a simple computer space ship simulation. This is just for fun to train my programming, 3D graphics and a little bit of physics skills. What I want is the user to pick a ...
0
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1answer
69 views

Why we get a force when a bus or car is going beside us? Is there any mathematical relation?

Suppose you are standing beside a road. A bus is running on the road, when it is crossing you, you feel a push of wind. Why its happen? Is there any mathematical relation?
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4answers
378 views

Why is $F=-\nabla V$?

I came across this equation $$F=-\nabla V$$ where $V$ is potential energy. I do understand that $$F(r)=-\frac{dV}{dr}.$$ Hence does this mean the nabla operator in this case means derivative? Because ...
1
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1answer
105 views

Forces that fall under gravitational forces

I was explaining the air motion in the atmosphere, so I introduced Gravity, Pressure Gradient and Coriolis Forces. Then one of the Professors asked me this question, which I couldn't answer. He said ...
0
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1answer
86 views

Why is the net work done in a pulley-string system zero?

In any pulley system, where the pulleys and strings are massless and frictionless, why is the net work done by Tension zero?
1
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1answer
52 views

Gravitational “acceleration” and frequency change of a photon?

For massive particles, force translates into acceleration which again is a change of the velocity vector in direction and/or magnitude. For a photon, the velocity magnitude cannot change, only the ...
0
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1answer
48 views

Firing a blank vs live round from a gun [closed]

When firing a gun, is there any difference between a blank round and a live round, aside from the obvious presence of a bullet exiting the muzzle? For example, does it sound different? Is there any ...
0
votes
1answer
46 views

Work done by friction on a body?

I know that when a body slides over a surface, the work done by friction is not stored as potential energy in the body. It is dissipated in the form of heat. But why is it not stored as potential ...
1
vote
1answer
48 views

Question about force in transverse waves on a string

In deriving wave equation or power transmission of wave transmitted by a string, it is usually stated (with some assumptions) that the transverse force on a point of the string is proportional to the ...
3
votes
1answer
63 views

Help understanding work

I have this problem: An object with 800kg mass is lifted up 2.4m by a force $F$. How much work does the Force do on the object (gravity is the only other force acting on the object)? From what ...
0
votes
1answer
61 views

Can I convert Power to Force?

I just realized that I have some issues with physics: I cannot just convert Power to Force (different units), $P = F * v$. But am I not able to calculate the force on a car that accelerates with a ...
0
votes
2answers
52 views

What is the meaning of this definition of potential energy?

The isolated system of particles is being observed. In the coursebook, $\vec F_\mu$ is by definition the vector sum of forces of all other particles acting on $\mu$-th particle. Usually, potential ...
1
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2answers
59 views

Concept of a Magnetic Field

I was reading a physics book by some author and I got a little too confused with the explanation he stated about magnetic fields. A magnetic field is a field of force produced by current-carrying ...
3
votes
2answers
110 views

Advantages of a deadblow hammer?

A deadblow hammer is a type of mallet with a hollow head filled with shot or sand. When you hit with it, say on an anvil, the mallet does not rebound, but just falls flat and heavy. I don't ...
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2answers
45 views

Does atmospheric pressure have a net contribution to this FBD (free body diagram)?

Pressure acting on the left and right sides of the block counteract
1
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3answers
131 views

Why dont we consider force exerted by atmospheric pressure in mechanics?

My school has started teaching fluid mechanics, and it really bugs me why we don't consider force exerted by atmospheric pressure in mechanics. I couldn't understand a word my teacher said. There is ...
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0answers
32 views

How Newton's third law is involved in a tug of war? [duplicate]

Using Newton's third law, we can say that each team applies the same force on the opposite team. Then how one wins? Is it due to ground friction?
0
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1answer
35 views

Interaction Energy vs Force

I'm having a hard time determining the relationship/differences between interaction energy and forces. Say we have a system of two charged particles. Each particle will exert a force on each other ...
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1answer
67 views

A question on Newton`s laws of motion [closed]

Question: Let there be a monkey $B$ which is holding on to tail of the monkey $A$ which itself is climbing up a rope. The masses of monkey $A$ and monkey $B$ are $M$ and $m$ respectively.If $A$ can ...
1
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2answers
45 views

Question on units for integrating F vs x graph

I had a homework problem with this graph of F(Newtons) vs x(meters). The graph has a straight line (constant slope) from (0,0) to (8,10). And the slope ((10-0)/(8-0)) came out to be 1.25, making the ...
0
votes
0answers
23 views

Measurement of drag (?) tension between two surfaces

I want to know if there are (reasonably inexpensive) devices to measure the tension between two surfaces. Beware of my terminology: the first help I need is to actually formulate my question ...
1
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1answer
27 views

About friction contributing to speed

Friction in our daily experience is understood as a resisting parameter to the effort putted for moving an object on a surface. I understand friction as a negative force by describing what happens to ...
0
votes
0answers
31 views

Why does every Action has a Reaction [duplicate]

I mean I know that when I exert a force on a wall the wall with exert it on me with the same force I did, but why, because of electron repulsion between my atoms and the wall's atom. I need to know ...
4
votes
4answers
259 views

Why perpendicular vectors do not share components?

I just can picture it in my mind or on paper. Can someone explain it with examples? This is the key idea behind the uniform circular motion: if the force has a component in direction of the object's ...
1
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0answers
31 views

Magnetic levitation project

For the past four years, I have been working on a project that will allow permanent magnets to levitate stably above a magnetic surface. So far I have tested my first theory which was to see if ...
1
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0answers
40 views

Reaction forces

If a cyclic lamina (in equilibrium) is supported from two points that are of equal distance from the line joining the centre and the lowest point of the circle (so the arrangement is symmetrical ...
-3
votes
1answer
59 views

Weight of magnetic objects and polarization [closed]

I am an Iranian engineer and have a question which no one has answered me yet. In weighing a strong magnet, there is a difference between the weights from different polarization directions, why is ...
0
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0answers
40 views

Force between magnets with different sizes

I would like to know how to calculate pulling or pushing force between two the same shaped magnet but with different sizes. Specifically, I'm looking for cylindrical and bar magnets. I tried solve ...