# 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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### 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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### Is the inertia of light equal to the inertia of mass under $E=mc^2$?

Under $E=mc^2$, 1kg of matter has $9\times 10^{10}$ joules of energy. So, if I had just the light shining from $9\times 10^8$ 100 Watt light bulbs inside a perfectly reflective box, would that light ...
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### What is the relationship between gravity and inertia?

What is the relationship between Gravity and Inertia? Einstein told us that gravity and inertia are identical. And from the fact that two different masses fall at the same rate, I believe we can say ...
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### Is it possible to measure inertial mass without gravity or rolling?

Is there a reliable (and ideally, easy to construct+tune) method of measuring inertial mass without using gravity (e.g. weighing on a scale or a freefall apparatus or a pendulum) or rolling (e.g. ...
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### Will variable but symmetrical density spheres which are otherwise identical swing at the same rate?

If you have a pendulum with the same length and different spheres on the end will the period be the same if the only variation is the distribution of mass from the center of the sphere? This is to ...
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### Why do gravitational mass and inertial mass appear to be indistinguishable? [duplicate]

I have learnt that heavier the object is (the more gravitational mass it has), the more resistance to the change of motion it is (the more inertial mass it has). I can accept this fact but I can't ...
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### Does Inertia “conflict” Entropy?

Earth continues to spin because of inertia. Does this fact "conflict" the entropy of the universe? Since the tendence is towards disorder, how is Inertia of planets Spin related to Entropy?
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### What determines the amount of inertia of matter?

what factors would increase or decrease inertia, i.e. require more or less energy to change the velocity of matter from what is currently required all else being equal? I have heard of mach's ...
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### What is the universal definition of 'inertia' in fields?

In my physics class we recently did the Gravitational Field unit, and the idea of gravitational field strength was introduced: $$g=\frac{F}{m}=\frac{GMm}{r^2}\frac{1}{m}=\frac{GM}{r^2}$$ After doing ...
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### Understanding the meaning of mass in Newtonian mechanics

So, I was reading a book on mechanics and there I found the following notion about mass. It says that "Experience shows that every body resists any effort to change its velocity,both in magnitude and ...
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### How does Newtonian gravity violate law of inertia?

I came across a line on http://physics.ucr.edu/~wudka/Physics7/Notes_www/node49.html " If the experiment is tried in vacuum any two objects when released from a given height, will reach the ground ...
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### Clarification regarding accelerating Car with packed environment

the question is when the car accelerates the atmosphere inside that packed car also accelerates due to the inertia but in a car (with height more than 10 feet) in which superman is in no contact with ...
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### What causes inertia? [duplicate]

Inertia forms the basis of Newtonian physics,but nothing really explains it.I know that it is generally accepted in classical physics,but can it's origin be explained?Maybe be relativity or quantum ...
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### Would a spinning object like a fan stop faster in a non-gravity environment?

Let's say there is a fan spinning and stops in exactly 1 minute on earth. Would it stop faster or slower or exactly same time in a spacecraft without gravity but exact same density of air. Btw: let's ...
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### Sensing fictitious forces

I need to clarify my understanding of fictitious forces and our sensation of them. It is my understanding that fictitious forces are terms added when Newton's laws are resolved in accelerating ...
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### How should one determine the motion of extremely large extended objects?

[To put this question in context, I was reading "How much time will it take to move an object whose length is equal to one light year?" and don't really feel satisfied by the answer that has been ...
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### Calculating New Velocity Vector of Moving Object [closed]

A 1kg object is moving through space. A force is applied to the object of 1N perpendicular to the direction of travel for 1 second. Assuming there are no other external forces on this object, (...