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Forces in tangentially-accelerating circular motion

Consider your experiment of a driver travelling in a circle. Now when you make the free body diagram of the driver, you can notice that the only force acting on the horizontal direction is due to ...
Science Tard's user avatar
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Resolution of Ehrenfest paradox using only special relativity

Let's say we have a turntable where any point on the perimeter has a instantaneous tangential velocity such that the gamma factor is 2. A ruler placed on the perimeter will length contract to half its ...
KDP's user avatar
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1 vote

Relative acceleration, mechanics

Perhaps it would help to think of relative displacement and relative velocity. Suppose m and M are on the table. Suppose M is at $x_M = -1 \space m$ and m is at $x_m = 2 \space m$. You can say what ...
mmesser314's user avatar
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1 vote

Resolution of Ehrenfest paradox using only special relativity

Instead of a solid disk, we might as well think of a circular train traveling on a circular track. Alice sits in the station. Bob is riding on the train. The Question: The track is shorter in Bob's (...
WillO's user avatar
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3 votes

Is angular velocity about any point in a rigid body always the same?

Doubt 1 It is measured about the axis of rotation. Doubt 2 Yes. For a rigid body all points will complete one revolution, $2\pi$ radians, about any axis of rotation in exactly the same amount of ...
Bob D's user avatar
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2 votes

Is angular velocity about any point in a rigid body always the same?

Each part of the rotating disk will have the same angular velocity. However, they will not all have the same tangential velocity (which will increase as you move further away from the axis of rotation)...
ABetheGammow's user avatar
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Do you always experience the gravitational influence of other mass as you see them in your frame?

These are excellent questions! They involve the interrelation of various physics concepts. And we would expect physics to be internally consistent, generally speaking. But since your insights are not ...
Colin MacLaurin's user avatar
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Motion of person in bus in inertial and non-inertial frame

A person is sitting in a bus that is moving with constant velocity, due to friction their is no relative velocity between bus and the person. If the bus is moving with constant velocity, no friction ...
Bob D's user avatar
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0 votes

Motion of person in bus in inertial and non-inertial frame

These effects are often called ficticious forces. I'll often call them pseudo forces, but I have found the best way to think of them is as accelerations. When you do the equations of motion in a non-...
Cort Ammon's user avatar
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Motion of person in bus in inertial and non-inertial frame

What we feel in an accelerating vehicle is the force from the seat back that is pushing us forwards so that we accelerate along with the vehicle. What we unconsciously assume is that there must be an ...
gandalf61's user avatar
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0 votes
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Motion of person in bus in inertial and non-inertial frame

My doubt is, if the fictitious force is not a real force why do we still feel a force pushing us backward while sitting in accelerating car? If you were somehow levitating in the bus as it ...
BioPhysicist's user avatar
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0 votes

Motion of person in bus in inertial and non-inertial frame

I think, If you are considering acceleration in any sense, you need to include the reference frame in which the acceleration is taking place. In 2nd person frame of reference, the one observing from ...
Samradh Bhardwaj's user avatar
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How does brain perceive time dilation due to gravity?

I believe since the person is on another planet with less gravitational force or medium or slightly less and the time to rotate the sun one complete rotation time varies from planet to planet. So ...
Subramanian G's user avatar
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Can the motion of a rigid body be decomposed into translational and rotational motion about ANY point?

A rigid body $B$, by definition, is such that, for every point $O\in B$ there is a triple of orthonormal axes ${\bf e}_1, {\bf e}_2, {\bf e}_3$ centered at $O$ such that the material points $Q$ of ...
Valter Moretti's user avatar
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What is the correct way to think of position?

Yes, that's correct. Position is a point in $n$-space, and velocity is its derivative. Integrating velocity, you get the change in position, a.k.a. displacement. Formally, position is $\vec r=x\vec{\...
controlgroup's user avatar
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What is the correct way to think of position?

Indeed. In many Physics textbooks position is assumed to be a vector in 3D space, defined as : $$ \textbf{r} = x \hat{\textbf{i}} + y \hat{\textbf{j}} + z \hat{\textbf{k}} \tag 1$$ then velocity is ...
Agnius Vasiliauskas's user avatar
2 votes
Accepted

Why do objects in circular motion move outwards instead of inwards?

I think the "ultimate" reason for this behavior is Newton's First Law. Any material body will continue in a straight line at constant speed, except as acted upon by a force, which will ...
RC_23's user avatar
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1 vote

Why do objects in circular motion move outwards instead of inwards?

When you swing a ball around in a circle, and suddenly cut the string, which way does it fly? Away from the circle. At any point during the circular orbit, the object has a tangential direction and ...
Steeven's user avatar
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1 vote

Why do objects in circular motion move outwards instead of inwards?

The straightforward answer is that : It happened due to the inertia of the pen cap ( or any object moving in circle ). Let me explain: Say , there is body on a horizontal , uniformly rotating , rough ...
CP of Physics 's user avatar
3 votes

Do you always experience the gravitational influence of other mass as you see them in your frame?

An easy way to see why this would not work: if you are moving rapidly, aberration makes most of the mass content of the Universe appear to lie in front of you. If gravity were based on apparent ...
Sten's user avatar
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1 vote

Do you always experience the gravitational influence of other mass as you see them in your frame?

The answer to the question in the title is "No." For a mass moving with constant velocity, the Newtonian approximation for gravity points toward the current position of the mass, not where ...
BaddDadd's user avatar
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0 votes

Tug of war between observers in frames with different rate of time

How the force changes along the rope depends not just on the relative redshift but also on the specific matter model for the rope. The equation that governs forces along the rope stems from ...
A.V.S.'s user avatar
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0 votes

Do you always experience the gravitational influence of other mass as you see them in your frame?

The contraction of distance and the contraction of the gravity field cancel out. The additional energy quite obviously causes additional force. I do not know how much additional force exactly. Force ...
stuffu's user avatar
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10 votes

Do you always experience the gravitational influence of other mass as you see them in your frame?

Unfortunately the whole premise of your questions is wrong. You seem to be trying to apply Newtonian gravity in a relativistic context, and that just doesn't work. You need general relativity to ...
Eric Smith's user avatar
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1 vote

Tug of war between observers in frames with different rate of time

I will address only question (a). Assuming sufficient distance that the gravitational pull on B is negligible (and, as stated in the question, that the gravitational pull on the rope is negligible), ...
Sten's user avatar
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1 vote
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Non-inertial frames in quantum mechanics

Inertial forces are completely described, in Hamiltonian mechanics, in terms of an electric-like potential plus a magnetic-like vector potential. The Hamiltonian of a free particle in a non-inertial ...
Valter Moretti's user avatar
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Two particles rotating about their center of mass

The center of mass is the geometric point of a rigid solid which acts as if all forces were acting on it. It is "indifferent" if that point in space coincides with a place where there is ...
JL14's user avatar
  • 67
-5 votes

Does time pass slowly in water?

Yes, according to Gries theory of observable light in a non-vacuum medium time inherently runs slower. However to the observer it remains constant thanks to relativity
Joe Gemino's user avatar
1 vote

Do off-centre forces create additional energy?

There is a standard demonstration in which an off-centre force is provided by a string wrapped around a cylinder on a air-table. Another string is connected to the c-of-mass of an otherwise ...
mike stone's user avatar
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0 votes

What is the relationship between gravitation, centripetal and centrifugal force on the Earth?

In this case, the centripetal force is the gravitational force. "Centripetal" and "gravitational" refer to two different aspects of the force: Gravitational refers to the source ...
Carmeister's user avatar
5 votes

What is the relationship between gravitation, centripetal and centrifugal force on the Earth?

The expression 'centrifugal force' can in most circumstances be understood as: 'a centripetal force is required'. In the case of the spinning Earth: At the equator the measured gravitational ...
Cleonis's user avatar
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2 votes
Accepted

Do off-centre forces create additional energy?

If the line of action of the force is not through the centre of mass then body can be thought of as being acted on by a force whose line of action is through the centre of mass which produces a linear ...
Farcher's user avatar
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3 votes
Accepted

What is the relationship between gravitation, centripetal and centrifugal force on the Earth?

Rotating reference frames can be tricky. Some of the trickery is that we typically only use them when it simplifies the math. This can make it tricky to separate the effects of the frame from the ...
Cort Ammon's user avatar
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5 votes

What is the relationship between gravitation, centripetal and centrifugal force on the Earth?

When confused, ditch centrifugal. Let us go back to the basics. The original Newton's 2nd Law (N2L) states that $$ \begin{align} \tag1\sum\vec F&=\frac{\mathrm d\vec p}{\mathrm dt}\\ \tag2\sum\vec ...
naturallyInconsistent's user avatar
0 votes

Why isn't a pseudo force considered for a block on an accelerating block?

When you analyze a system using $F=ma$ and $a$ is non-zero, that doesn't mean it is not an inertial frame. You are analyzing the motion from the "laboratory frame" attached to the floor, ...
RC_23's user avatar
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0 votes

Can there be a theoretical synchronised ‘now’ moment at all points across the universe?

A good explanation of what Now means in a relativistic framework. I do have some critical comments. That a light cone defines the area from which information can be received by an observer, this ...
Daniel Jencka's user avatar
2 votes
Accepted

When you are in a gravitational field, do object far away get physically closer to you as you get closer to the mass?

This is to answer the latest version of the question, as phrased in the comments: I should have clarified in the question [...] The only thing that truly matters is clock ticks counted by each ...
safesphere's user avatar
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4 votes

What is the physical significance of Moment of Ineria about a point vs Moment of Inertia about an axis. In which types of problems we use the former?

As described above, the inertia tensor is 2nd moment of the mass distribution: $$ I_{ij} = \langle ||r||^2\delta_{ij}-r_ir_j \rangle $$ and it contains 6 numbers that describe the rotational interia ...
JEB's user avatar
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1 vote

Relative speed in unpolarized cross-section

The velocity difference of the two can of course be $2c$, observed from the frame where $v_A = +c$ and $v_B = -c$. If, however, you would be in a co-moving frame with e.g. particle $A$, then you will ...
Jesse's user avatar
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4 votes
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What is the physical significance of Moment of Ineria about a point vs Moment of Inertia about an axis. In which types of problems we use the former?

Inertia tensor In mechanics, for general problems in 3-dimensional space, rotational inertia of a rigid body is represented by a tensor, namely the inertia tensor $\mathbb{I}_P$. Inertia tensor is a ...
basics's user avatar
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2 votes

What is the physical significance of Moment of Ineria about a point vs Moment of Inertia about an axis. In which types of problems we use the former?

They are the same thing. Rotation is always around an axis. Often people people think in $2$ dimensions instead of $3$. They talk about a flat object rotating in a plane. The axis is perpendicular to ...
mmesser314's user avatar
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0 votes

Pseudo Orbital motion only due to Coriolis force

In the case you are asking about: Describing the motion relative to the rotating coordinate system requires more than the coriolis term; the centrifugal term is necessary too. In total three terms are ...
Cleonis's user avatar
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3 votes

A pop pop boat heated with a self-contained heat source and run in a superfluid appears to show a preferred frame

Making the medium a superfluid doesn't seem to change much here. It still has to enter the vessel and then be ejected. Because the ejected fluid will have some speed relative to the boat, the boat ...
BowlOfRed's user avatar
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1 vote

Pseudo Orbital motion only due to Coriolis force

This is certainly possible. However, it's much easier to visualize what happens by thinking about the inertial frame first. Specifically, if an observer launches a projectile "vertically upwards&...
Michael Seifert's user avatar
0 votes

Pseudo Orbital motion only due to Coriolis force

How to calculate escape velocity actually you can look at escape velocity
sayed's user avatar
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0 votes

Circular motion - object sliding down a hemisphere

You were right when you said "I think that the assumption that the only force the ball exerts on the [hemi]sphere is $mg \cos \theta$ might be wrong". You may have thought this by thinking ...
Anis Manuchehri-Ramirez's user avatar
14 votes
Accepted

Why, when we calculate forces in banking of roads, we do not take the centripetal force but the centrifugal force?

Define the "outward" direction in your diagram (to the left) to be the positive $x$-direction, and define the vertical direction to be the $y$-direction. In the inertial reference frame, ...
Michael Seifert's user avatar

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