# 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!

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### Where exactly is inertia stored? [closed]

Suppose you have the power to take a snapshot of an object containing all its information. Say a ball was thrown to a direction to your right and you took a snapshot of it. This snapshot contains all ...
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### Isn't inertia experience by person in moving bus same as torque

When a bus moves suddenly, the person standing in it tilts backwards. This concept is explained using inertia(tendency of body to resist change in its state of motion) but when the bus moves suddenly, ...
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### What if Force was not Mass times Acceleration? [closed]

We know that Force equals Mass times Acceleration, $F = ma$. But what if we had a law like $$F=m^2a$$ or $$F = 2ma~?$$
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### Why is the ratio of gravitational force and the inertia to resist it 1?

Is there a deeper meaning behind how things of different mass fall at the same acceleration? It feels so perfectly balanced...
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### When do we illustrate inertial forces on inertial frames of reference?

I came across two practice questions wherein an object was attached to an accelerating vehicle, yet only one of these cases required an inertial force to be illustrated on the object's free body ...
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### How does the inertia of granules within a rotating cylinder affect its inertia?

If a cylinder is partially filled with granules and is rolling down an inclined plane, is there any relationship between the rotational motion of the granules and the motion of the cylinder? I'm ...
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### Why does mass cause resistance to acceleration?

If I were in a vacuum with no gravity or friction, why would it be harder to push a floating bowling ball than a marble? Is there anything happening on an subatomic level that makes matter act ...
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### Why doesn't a ball thrown upwards fall behind us if we're moving forward?

If we consider ourselves traveling in a bus and if we a throw a ball upwards, the ball should fall behind us according to law of inertia, right? If so why doesn't the ball always fall behind us each ...
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### Convert inertia formula to excel calculator

I've been looking at this question: "Weight" of moving object in a car collision but to be honest I can't get my head around how to work it out myself (I'm not a physics student!). What ...
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### Spiral lamp chane state speed [closed]

Question is how fast halogen lamp reach it full temperature, going from cold (not light) state to full light emit state. how fast in milliseconds it takes, imagine: if led lamp work instantly like 0 ...
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### Inertia of a falling weight

I use a standard device (penetrometer) that uses a 10 kg weight that is dropped a constant distance to cause a probe to penetrate soil. The penetration distance after 4 blows is recorded. If I were to ...
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### Relation between Fisher Information Matrix and Inertia Matrix

I have been wondering whether there is a relation between the Fisher Information Matrix in a stochastic particle system and Inertia Matrix?
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### Calculating inertia of motor

I'm currently working on a project, and for futher calculations down the road (the controller of the mechanical system) I need to calculate, as accurately as possible the interia of the system. I'm ...
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### Which fundamental force underlies inertia? [closed]

We learn about the four fundamental forces (gravity, electromagnetism, strong, weak). I am curious about how these four forces mediate/cause/drive everyday phenomena. In particular, it has never been ...
962 views

### Why is Quantized Inertia considered pseude-science? [closed]

In the criticism section of the Wikipedia article to Quantized Intertia it is stated that QI is considered pseudo-science. Unfortunately none of the linked but in none of the provided links can I find ...
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### Cube tumbling over

When a moving cube hits a low step (the step is perpendicular to its velocity) and tumbles over, is its angular momentum conserved? It is implied that it is so, but certainly gravity produces a torque ...
33 views

### Calculate stroke force and angle for a ball rolling on a surface to reach a destination position (optimal golf putt)

I'm trying to find an algorithm which calculates the optimal golf putt (angle, force) given a 3D surface (obtained through Poisson reconstruction), start and destination position (hole). I guess that ...
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### Couldn't we always redefine units so that inertial mass and gravitational mass are equal?

It is a known fact that inertial and gravitational masses are the same thing, and therefore are numerically equal. This is not an obvious thing, since there are even experiments trying to find a ...
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### If centrifugal force is fictitious, what force is real in its stead?

Here's an example illustration: The way I understand it, when the car starts turning, the centrifugal force at first does not exceed the force of friction, which allows the car to stir. But at some ...
368 views

### What is meant in mass' definition 'resistance to acceleration'? [closed]

Wikipedia: Mass is both a property of a physical body and a measure of its resistance to acceleration What does this mean? I know of the $E=mc^2$ formula. I think, the energy required to '...
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### Why is Disturbance Force Equal to Total Force in Stokes Flow?

So this step confuses me. Why is it true that the disturbance force is the total force in stokes flow? Any advice or guidance would be great! From Pozrikidis' book:
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### Calculating weight needed for a fixed pole

Imagine a game of swing ball, where the rope is 1m long, and the ball weighs 1kg. How do you calculate the weight that the pole has to be so it does not get pulled over, assuming it is not burried in ...
150 views

### How does inertia work at the particle level?

I've read recently that the mass of a proton is mostly not given by the Higgs mechanism. But rather it's given by the energy of quarks moving around inside the proton and gluons and other internal ...
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### What's the seconde moment of a T beam with a heel?

the seconde moment of area of a rectangle is Iy = (bh^3)/12 b : base h : height What is the second moment of area of a T beam like this one ?
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### Centrifuge Artificial Gravity?

I just saw the following video: NASA centrifuge. In video, a person is walking on a huge spinning centrifuge. But his weight is still acting downwards and there is no supporting force which will keep ...
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### Inertial and non-inertial frame

How to define an inertial frame of reference mathematically? I want a definition with proper chosen coordinate axis which will help me to differentiate it with the non inertial ones. I have been ...
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### Do the inertial mass and gravitational mass of an object depend on the frame of reference?

My understanding is that the "relativistic mass" of an object means any of the following three quantities (which are all identical): The "mass-energy", as defined by the formula $m = E / c^2$. The ...
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### Faraday's Law and the Law of Inertia

Faraday's Law can be stated qualitatively as : Any loop (of wire) opposes/resists the change of magnetic flux through it. The Law of Inertia states that any physical object resists its change in ...
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### Does buoyant force become less effective as acceleration increases?

Lets say a balloon with a certain amount of buoyant lift has a 2 kg mass strapped to it (including engines) and accelerates enough that it perceives a positive 2.5 g inertial force (2.5g * weight) ...
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### Inertia when pulling on a rope [duplicate]

Imagine a fragile cord attached to a ceiling with its other side attached to a sphere. On the lower part another cord is atrached to the sphere. Now visualize you pull STRAIGHT downward on this cord. ...
4k views

### Difference between Mass and Inertia

My questions is about mass and Inertia, what is the difference between Mass and Inertia? Are they the same or different? How? I am really confused with it,some says mass is the measure of Inertia, ...
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### Are mass or inertia the same thing, the same properties?

I think so. But I wold like to know another opinions to confirm.
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### Overcoming the inertia of a body at rest

Neglecting friction and other forces (air resistance) and assuming all forces are orthogonal the gravity vector , consider a large dense sphere at rest on a perfectly flat plane which is plumb. Now ...
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### Total energy of an object in motion in free space

In order to impart motion (additional motion) to an object in free space, inertia "soaks up" an given amount of energy prior to additional movement, which is related to its mass, irrespective of any ...
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### Can the origin of mass or inertia depend only of the gravitational field of matter? [closed]

The gravitacional field is directly proportional to mass or inertia. It doesn't have another property or field like this, with this power. I think that when we apply a force to an object, the ...
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### Inertial stresses in Reynolds number

What is meant by the inertial stress in the definition of Reynolds number? Reynolds number = Inertial stress/ viscous stress
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### Why do 2 bodies of different masses reach the ground at the same time? [duplicate]

Since inertia is the quantity that resists change in motion, and is represented by mass, and if two different objects are dropped from the same height, shouldn't the heavier mass accelerate less than ...
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### How do I convert cardinal axis inertias to an arbitrary axis inertia?

I've tried to reduce this problem to the most basic form. I know the equation for a spring-mass system is generally: $$F_{\mbox{applied}} = kx + m\ddot{x} \\$$ but, in my case, I have a spring ...
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### Explanation of the classic jerk and pull string system [duplicate]

It is known that when we jerk the bottom string quickly, it will break; and if we pull slowly the top string will break, while the force applied is the same. My confusion is: according to Newton's ...
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### Inertia on a rotating disc?

If I toss a ball upwards in a train moving with uniform velocity, the ball will land right back in my hand. This is because the ball has inertia and it continues to move forward at the speed of train ...