# 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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### Why is inertia connected with mass and not momentum? [duplicate]

When my teacher was teaching us $E=mc^2$, he told us that the relativistic mass of an object increases when the speed increase. He told us that it is due to the increase of inertia. He said that as ...
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### Thought experiment in Mach's principle - Can a void universe be considered with special relativity?

Mach's principle is based on a thought experiment in which an astronaut floats in the middle of a space devoid of all matter and all landmarks. No star, no source of energy is present, whatever the ...
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### Electromagnetic Waves and Inertia

I have a conceptual question. Suppose we have two bodies of equal masses. One is electrically neutral and the other is electrically charged (positivley charged). Now we apply equal magnitude of force ...
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### Would you run faster on Mars?

Given the 1/3rd of Earth's gravity on Mars and neglecting space suit limitations and also assuming you have maintained your muscle strength, would you run faster on Mars? The answer may not be so ...
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### Is inertia present at the level of elementary particles?

Is a more massive elementary particle will experience more inertia in a one-on-one particle interaction?
1 vote
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### Red shift/Blue shift as a standard for determining absolute motion

If I begin standing, I can imagine that there are photons of various wavelengths arriving at my location from all directions. If we eliminate local energy coming from stars and radiating bodies, ...
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### How to calculate the gyroscopic inertia for this exact experiment?

This question refers to the photo below. The wheel in the middle can rotate vertically without friction. The construction around it can rotate the wheel horizontally as well, also without friction. ...
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### Walking pace and torque

How to understand the relationship between the mass of a person, the length of the legs and the walking pace? My professor tried to explain it but I didn't quite get it. So we can consider the hips as ...
1 vote
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### Water flowing after turning off pump

I'm pumping water with a mini pump through a plastic hose (1 meter), between two glass containers. My problem is that if I turn off the pump when the water is flowing through the entire hose, water ...
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### An elevator moving with constant velocity

While an elevator moves up, it moves up with a constant velocity. I read this post and understood that it's because of inertia. However, I'm not really convinced. So what happens which I have ...
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### Inertia of an elevator

Imagine a situation where we have a relatively light empty elevator moving up at a pretty high constant velocity say something above $10\ m/s$, just so that it has a considerable amount of momentum ...
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### Does inertia imply that a cyclindrical mass in frictionless motion on a horizontal plane keeps moving forever ( with $\vec F = O$)?

Suppose I have a perfectly cylindrical pencil and set it in motion on a perfectly smooth and horizontal table, in such a way that the axis of the pencil is in translation. Is the state of this object ,...
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### Moment of inertia of the water flowing through a freely-rotating cylinder

I want to model the kinematics behind a mid-air bottle-flip, in order to find the probability of the bottle-flip being successful given initial conditions. This is for my high-school mathematics ...
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### The impact of mass distribution on time taken for a cylinder to roll down a ramp

I am carrying out an experiment to test out the impact of mass distribution on time taken for a cylinder to roll down a ramp. I have kept the overall mass of the cylinder constant, as well as the ...
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### Is pseudo force another form of inertia observed from accelerating frame of reference?

We know that pseudo forces act when we opt for non-inertial frames of reference. Is pseudo force another form of inertia observed from accelerating frame of reference?
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### In the context of General Relativity, does having gravitational mass imply resistance to acceleration?

My question is essentially this one, but since that one never got a satisfactory answer, and it's of such fundamental concern, I'd like to try asking it in a different way. The question is whether ...
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### Newton first law of motion

The State of rest and the state of uniform linear motion are equivalent. Why?
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### Does time causes inertia? [closed]

As you know inertia is an behaviour of matter that objects resist change in their motion. If an object is at rest it will remain at rest and if an object is moving with a constant velocity it will ...
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### Photon follows law of inertia? [closed]

Is the law of inertia compatible with quantum mechanics? If yes, how? And if a particle is both present and absent at the same time, (the uncertainty principle: stating that when an electron is on ...
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### Decrease of the rotation speed of a wheel with inertia, when we stop applying rotational force to it [closed]

Let's say we have a wheel rotating at a constant speed $s$. Suddenly at time $t=1$ we stop applying force to it. What is the law for the decrease of the speed, until it stops? I guess it will look ...
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### Forces on us on a rotating Earth

So the earth is constantly rotating but it doesn't need a force to rotate. It'll rotate indefinitely.(?) But we and other masses on earth need a force on us to continue rotating along with earth? And ...
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### An object on top of a rotating mass like earth

Why do objects fall down in same place on the rotating earth? I get that newton's first law is the reason an object falling on a high speed train will maintain the same velocity as a train and ...
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### When a car accelerates relative to earth, why can't we say earth accelerates relative to car?

When a car moves away from a standstill, why do we say that the car has accelerated? Isn't it equally correct to say that the earth has accelerated in the reference frame of the car? What breaks the ...
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### Very strange published papers on Mach's Principle

I have recently come across a set of peer-reviewed conference papers (https://petermarkjansson.com/research/machs-principle/) reporting observations of electromagnetic markers of Mach's Principle. In ...
1 vote
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### How to calculate HP knowing flywheel weight

So I've seen a guy on Youtube that has an RC nitro engine. He attached a quite big flywheel of known weight to its output, and then by measuring the time that it takes to reach max rpm he was able to ...
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### How is Newton's first law of motion different from Galileo's law of inertia? If the two are the same, then why is the first law named after Newton?

Galileo's law of inertia (at least what I've learned) is "A body moving with constant velocity will continue to move in this path in the absence of external forces". And Newton's first law ...
I'm trying to work out the moment of inertia (i.e. what would be $I=mr^2$ for a point mass) of the volume of rotation around the y-axis of a square with side length a, at a radius along the x-axis R, ...