Questions tagged [inertia]
Inertia is the tendency of a body to oppose changes to its state of motion. DO NOT USE THIS TAG for moment of inertia or inertia tensor!
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Inertia in a different medium than air or vacuum
I have a problem understanding inertia in a medium more viscose than vacuum or air.
Let's consider the classical bus experiment.
The bus (a closed system) is accelerated or decelerated and a person ...
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Why does parallel axis theorem only work when one axis has gone through the center of mass?
By setting the origin at the center of mass, and the coordinate of P axis being (a,b) the formula should be derived by the following method:
$$I_{CM} = \Sigma m_{i}(x_{i}^2 + y_{i}^2)$$
$$I_{P} = \...
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Disc deceleration with flexible shaft [closed]
If a disc with a large inertia is being driven at a constant speed via a flexible shaft, and a constant brake torque is applied to the end of the shaft (away from the disc), will the disc deceleration ...
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Clarification on Momentum vs Inertia in Exerting Force when Stopping
I encountered a physics question in an exam four years ago that I believe may have had an incorrect answer key. I'm seeking clarification on the correct concept.
The question was:
The property of ...
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Case study on inertia
When our upper body and lower body both are in contact with bus then after applying breaks why only upper body part moves forward?
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Why do we have an opposing force in dynamic equilibrium? [duplicate]
I found this definition in my textbook about how dynamic equilibrium works. I was wondering if the opposing force is equal to the given force such that the net force is 0. Wouldn’t that mean that the ...
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Why isn't the moment of inertia the rotational analog of INERTIA?
I've thought that both mass and the moment of inertia measure an object's inertia, one being in translational motion and the other in rotational motion. That has made complete sense to me, but in my ...
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Why does binding energy of particles, which constitutes most of macroscopic mass, make them harder to accelerate?
I've seen a lot of questions on this topic so please don't misunderstand, I understand E = mc^2 and SEMF and so on. I specifically want to know how internal forces within lets say a nucleus make it ...
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Evolution of a rotating system in which mass continually leaks [closed]
this might be a trivial problem but me and a friend have failed to solve it. This is not homework, it actually relates to a book of mine but that is of no interest. Imagine the following;
Two masses $...
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Mass moment of inertia flipping in different mediums
Consider someone performing a front flip in the water versus in the air. Assume the body position in both cases to be identical. In which case would the mass moment of inertia be greater and why?
Prof ...
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Is this the correct way to integrate orientation given torque and inertia tensor?
I am trying to develop a 3D rigid body simulation in C++ in which I had some conceptual doubts on how to integrate for orientation given the total torque applied to a rigid body, and it's initial ...
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Geodesic equation: Bridging the gap between inertia and gravity
The geodesic equation can be expressed as:
$$\frac{\mathrm{d}^2 x^\mu}{\mathrm{d}\tau ^2} + \Gamma _{\alpha \beta} ^\mu \frac{\mathrm{d}x^\alpha}{\mathrm{d}\tau} \frac{\mathrm{d}x^\beta}{\mathrm{d}\...
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Can we achieve infinite movement from one initial burst of energy?
If there was a large enough vacuum chamber, and it was a perfect vacuum, could we potentially throw something and have it move infinitely? When you throw something, say a football, it travels through ...
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What would be an experimental test of Sciama’s theory and why it has not been pursued yet?
Recently I came across a video were the origin of inertia was attributed to Sciama’s paper (1953).
I have seen only a couple of questions regarding this topic on Stack Physics. Both of them are ...
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Did Newton know that light has no inertia? [closed]
Newton studied a lot about optics and gravitation. Did he realize to some extent that light is a massless particle? How does his theory explain the bending of light due to a gravitational field?
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How to calculate time needed by an object to change its state of motion when an net force applies to it (inertia)?
(Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This tendency to "...
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In a moving car / bus when the car suddenly accelerates do we go back due to inertia or is it due to pseudo force?
When an car moves forward we go back and we have always read that the reason was that our legs stay in contact with the ground and our body goes back since it was at rest and with sudden motion it ...
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Why the orientation of an object on Earth rotates with the rotation of earth? Is this due to friction?
The moon always faces toward Earth. That's because the moon rotates itself while revolving around the earth. This might be the result of tidal force for a long time, but what about objects on Earth? ...
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How do you calculate kinetic energy in a convention where the one-way speed of light is anisotropic?
The question about measuring the one-way speed of light has been debated in several posts in this forum, and are treated in detail on this wiki page.
In relation to this debate, I wonder how you would ...
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Maxwell's wheel - moment of inertia vs damping coeff
I am investigating the relationship between the moment of inertia of a yoyo-like apparatus (maxwell's wheel) and its damping coeff. I am adding disks to my yoyo to change its moment of inertia, which ...
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What is exactly particle inertia in a fluid-particle mixture?
In a mixture of a cylindrical particle and the carrier fluid, what exactly particle inertia refer to? (let's neglect gravitation force and Brownian motion).
When the size of particles are small (...
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What experiment should be conducted?
Im self studying physics and came to this question in my textbook:
A passenger in a moving bus with no windows notices that a ball that had been at rest on the aisle suddenly start to move towards ...
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Can added mass depend on stochasticity of motion?
Can added mass (also called virtual mass or induced mass) of a voluminous object in a massive fluid surrounding be affected by some stochastic motion of the mass (relative motion between the object ...
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How does Newton's First Law show the existence of inertial reference frames? [duplicate]
Newton merely stated the law of inertia as:
An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced ...
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Does it take more energy to bring a car to a halt if it is still accelerating on impact than travelling at constant speed?
So, my physics is quite rusty, been out of varsity for a while.
A friend asked me this and I am still pondering. Here is the scenario:
2 Cars are travelling towards a wall, and make impact with the ...
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Why does the ball in Galileo's double inclined plane experiment reach the same height?
Why does the ball in Galileo's double inclined plane experiment reach the same height? I know how to show it by energy conservation law but am unable to prove it by the equations of motion. Can anyone ...
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Can someone explain 'virtual mass' in fluids in simple words (for a dummy/high schooler)?
so I recently came across the term 'virtual mass' and when I looked up more about it, it just gave me some stuff about fluid mechanics that I dont understand properly. My understanding of virtual mass ...
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Can the inertia factor of a black hole be used to infer its density profile?
The Sun's inertia factor of ~0.07 suggests a stark contrast between the density of its outer shells (very low density) and its core (very dense). The same applies to the rest of the solar system. ...
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What's the reason an airplane turning 180° from strong headwinds causing it to have no ground speed does not stall?
I saw a video of a small propeller plane hovering over the ground due to strong headwinds but then turns 180 degrees and flys away. I was trying to figure out if the plane shouldn't be stalling ...
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Inertial Mass = Gravitational Mass. Why? [duplicate]
Okay, so the inertial mass of an object is always equal to the gravitational mass of the object. Conceptually, however, they seem different. Then what makes them identical? Is it because they are ...
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Tree falling without inertia while people stay suspended in air for a split second due to inertia
I recently saw a video ( watch it 0.5x speed ) of a slanted coconut tree on the bank of a river in India breaking due to the weight of the kids who climbed on it.
The tree seems to have broken near ...
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Doubt regarding lifts (and inertia?)
so i was thinking about lifts and i am confused.
let's say there is a body within a lift (system at rest). Now if the lift starts to accelerate downwards with say an acceleration a ($a>g$). The ...
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If a stone is dropped from a hot air balloon, is the initial velocity $u=0$, or is it equal to the velocity of the balloon $u=V_{balloon}$?
In theory, since the stone acquires the velocity of the balloon, it should go upwards slightly before coming down since it's velocity is equal to that of the balloon (in upward direction). But ...
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Why we can take for granted that energy binding is associated with inertial mass?
It is common to state that a proton is bounded state of three quarks, and that the QCD energy binding (associated to a "cloud" of gluons joining together the three quarks) is responsible for ...
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Does the bias in a loaded die depend on gravity?
Suppose I bias a cubic plastic die by incorporating a lead pellet hidden just behind the '1' face, so that the probability $P_6$ of rolling a 6 is greater than the symmetric 1/6. Its exact behaviour ...
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How does inertia affect an object suspended in a fluid?
When I asked my physics teacher how fully submerged objects are suspended in fluids, she told me it was because the object's density was equal to that of the fluid's as a result of the net force ...
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Calibrating an inertial measurement unit (IMU) to zero/flat surface
I am building a digital spirit level using an inertial measurement unit (IMU), and I want to calibrate the device so that it shows the angle correctly. Does anybody here have experience with this kind ...
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Using the principle of inertia to motivate the principle of least action?
Can we motivate the principle of least action with the principle of inertia that causes a mass particle to resist changes in its momentum? After all, the principle of inertia is the starting point and ...
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Why are the masses hanging from a pulley not considered in its moment of inertia?
My physics textbook showed a diagram of a pulley with mass with 2 blocks hanging from either side by a massless string. They calculated the moment of inertia by finding an approximation of the pulley ...
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Observational status of Sciama's hypothesis
I have always taken the existence of inertia more or less for granted, as an observational fact that does not require explanation.
But on reflection this is an unscientific attitude, and perhaps there ...
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What is happening on an atomic level (or lower) when a object is in motion (inertia)?
If you have an iron ball and throw it upwards you are imparting a force which opposes gravity.
Initially this force is easily understood by your hand pushing the ball upwards, so the atoms in your ...
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Propellant less propulsion when there is nothing to push against
Is there a way for a vehicle to move without losing mass when there is nothing for the vehicle to push against? For example, a helicopter flying around in a vacuum.
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Inductance - a better analogy than the fact that it is similar to inertia
This question is to get a feel and good definition for what inductance actually is.
I have read about the analogy where inductance can be compared to inertia-that the flux through an inductor resists ...
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How are objects kept free falling in the LISA experiment?
I'm watching a video about the LISA experiment, which will be used to detect gravitational waves.
In there, three space stations will be launched and will follow the Earth in its revolution around the ...
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How do I convince my students the Newton's first Law is the way it is?
Every time I teach this law, there are always a few students asking me why a net force is zero on a system moving at a constant velocity. This group of students takes physics for the 1st time. It is ...
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How density of fluids is would affect inertia?
I was watching that movie Event Horizon and they use water as an instrument to protect passengers of a space vessel from 30G acceleration, so my question is about a similar scenario, what would happen ...
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Newton: an object in motion remains in motion: was there anyone else who believed this? [closed]
From my own experience as a schoolkid, that was the law that I was not buying. I could see his understanding of the Lunar orbit making him think this but otherwise, what in human experience would lead ...
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Equivalence of Inertia and Gravity [duplicate]
I'm now wondering...does - energy=mass=inertia=gravity? Are they all, intrinsically, the same, "thing"; that is, the same, "entity".
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How does classical, Newtonian inertia emerge from quantum mechanics?
From my understanding, inertia is typically taken as an axiom rather than something that can be explained by some deeper phenomenon. However, it's also my understanding that quantum mechanics must ...
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How to mathematically express and then optimize my photon emitter? [closed]
A laser shoots photons directly at a flat disk with a fixed linear rate f(t) on the interval [t0=a,tn=b] with a horizontal path.
E.x. f(t)=100 photons per second
The laser is controlled by robotic ...
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