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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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Car physics Braking and Accelerating

Why does a car nose up when accelerating and nose down when braking. and when i try to move in reverse with the handbrake on the car rear move up ?
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Hyperloop without acceleration feeling

I have a question about hyperloop. Is it possible to create a hyperloop with high acceleration and that the passengers dont feel the acceleration, theoretically speaking? And is a situation possible ...
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torque and infinite moment of inertia

As a continuation of the previous question here: torque in zero gravity Say we have two coaxial drums with known moments of inertia $J_1$ and $J_2$. If the first drum contains a motor, which acts on ...
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Does modern physics have any explanation for what causes inertia? [duplicate]

I remember Richard Feynman stating on a few occasions (like here, in lecture 1, around 21:10) that physics has no explanation of what causes inertia, that it seems to be some sort of deeply mysterious ...
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How to measure propulsive efficiency of a human powered boat? [closed]

I am asking for help to measure the effective propulsive force and its effect on boat glide on a human powered vessel using a paddle. Senario A person using a paddle to propel a boat or canoe. ...
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641 views

Inertia of a Car?

I was reading through my driver's manual, when I came across this picture: I don't think the inertia arrow is accurate: inertia/momentum would be pointing directly forwards, while centripetal force ...
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calculation of moment of inertia referred to motor shaft?

Is this equation valid for a given mechanical system The Inertia of the motor is $J_m$,there is no loss in the system.then conservation of energy can be used. the motor is revolving with speed $\...
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1answer
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If velocity is relative, how can mass (inertia) be coordinate independent?

Would inertia grow differently if we switch the reference frame? LHC accelerator makes protons x7000 heavier at record speeds and I just wonder if we could change the reference frame (keeping ...
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439 views

Why can't Pseudo force from our frame of reference be a form of Inertia?

Let's assume that we have a person sitting on a bus. Suddenly the driver applies brakes, such that the direction of acceleration is opposite to that of motion.If the person draws the Free body diagram ...
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Would you be able to get off of a frictionless surface?

Imagine that you are standing (naked) in the center of a level circular disk (with a radius of, say, 3 meters) that is completely frictionless. Without resorting to blowing air or excreting any ...
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Simple mechanics : Bar stuck to a point on the ground: Inertia problem

So, given the following bar, stuck to the ground at point O, I know its mass, the angle it makes with the vertical axis that goes through the point O, I know the bar's length and its initial velocity, ...
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Inertia tensor integral

$$I_{xx}=\sum{m_\alpha}(y_\alpha^2+z_\alpha^2)$$ $$ I_{xy}=-\sum m_\alpha x_\alpha y_\alpha $$ How can these two definitions of the inertia tensor be combined into one definition to get $$ I_{ij}=\...
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Mass, Weight and Inertia

In The Feynman Lectures on Physics Vol-1, it is written How hard it is to get a body going is one thing, and how much it weighs is something else. Weight and inertia are proportional, and on earth'...
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What is mass (not weight)

I just read this Wikipedia article on what is mass and according to it mass is "the measure of an object's resistance to acceleration". However, that doesn't make sense, for example here on Earth ...
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Energy required to stop a rotor

If I want to stop a rotor going 8750 rpm with a moment of inertia .0325 kg m^2 then do I just calculate the kinetic energy the rotor has and that's my answer? and if so would I make it negative
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Is it right to say That Inertia of rest is more preferable than inertia of direction? [closed]

A). What is inertia basically, i think it is the resistance of a body to remain at that state. so whenever i try to change the inertia of a body it resist that change, to overcome that ...
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1answer
199 views

Why does the bicycle move forward after I give it an impulse with the help of brakes?

Whenever I need to slow down my bicycle I use brakes, momentarily pressing them and then releasing. For some reason, this momentarily halts the bicycle and when I release the brakes, the bicycle ...
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Why Objects still move under the effect of fictitious force?

As I read in many books and websites, An inertial force is a force that resists a change in velocity of an object. It is equal to—and in the opposite direction of—an applied force. If the inertial ...
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Does a rope connecting an object to a constant-velocity aircraft fly at an angle?

A massive object is hanging by a massless cord from an aircraft. The aircraft is moving at a constant velocity v. Even assuming that air resistance exists, shouldn't the cord be perpendicular to the ...
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1answer
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Off-center propulsion of space ship : Does it travel in a straight line or rotate? [duplicate]

I'm designing a space ship for a comic I'm writing. I was just finishing up the first sketch when I thought whether such a design would actually be possible. Hence my question: A spaceship is located ...
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1answer
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Confused About Physics In MythBusters Knight Rider Experiment

I am confused by the nature of the basic physics that occured while watching the MythBusters Knightrider Ramp Experiment. To summarize the experiment, they wanted to see if a car could safely drive up ...
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Is this the correct way to think about why static friction is directed radially during a turn on a level surface?

So after much pondering of the fact that the net static friction force points in the center, perpendicular the tangential motion, I thought of this explanation. If we look at a car travelling around ...
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Inertia of a box of photons

Suppose a box one light year long (along its x-axis) with some mass M also contained a bunch of high energy photons with energy E that were travelling along the x-axis. Would the inertia of the box ...
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1answer
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Does any higgs theory encompass accleration? Or is there a theory that encompasses this idea? [closed]

I figure that either there's : 1) Already a theory that encompasses this idea, or a better idea to explain what I'm trying to visualize. 2) perhaps some sort of proof why this is wrong. 3) Everyone ...
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Effect of density and volume on inertia

I recently came across this question : What will be the effect on inertia if - - density is halved - volume is one third I searched about it but everywhere ...
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Physical meaning of the moment of inertia about an axis

In the context of rigid bodies, the inertia tensor is defined as the linear map that takes angular velocity to angular momentum, that is, the linear map $I : \mathbb{R}^3\to \mathbb{R}^3$ such that $$...
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Which factors can help a car flip on a turn?

I am not sure if this is the right place to ask it, but this is a question that I thought today, and it gave me some curiosity to understand. Imagine that a car will curve, we can say the turn is a ...
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Does Inertia really define the resistant ability of a body

I was reading the chapter Newton's 1st law of Motion , where I met the definition of Inertia. The property of an Object by virtue of which it neither changes its state nor tends to change the state,...
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Influences on wavefunction path analysis

I was looking at simulations of a wave going through a slit. When the wavelength was much smaller than the slit width, the wave went through the slit and kept going straight like a laser beam. But ...
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A bullet makes a hole but a rock shatters the glass

Consider a bullet fired toward a pane of glass. Barring slight cracks, it creates a relatively clean hole in the glass. On the other hand, when a stone is projected toward the same glass pane, it is ...
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Golf ball curving to right or left when putting along a slope

I will use the example of a golf ball here, but there are many other examples I guess. My question is: A golf ball is at rest on an incline that slopes from right to left. I take it the force from ...
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441 views

Is it necessary that the path of an object in uniform motion is a straight path? [closed]

What does the path of an object look like when it is in uniform motion?
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If inertial mass were equal to for example half of gravitational mass why would things not still fall at same rate?

I have read that it is the equality of inertial and gravitational mass that causes all objects to fall at the same rate irrespective of size. But if this were not true, what effect would we see? Would ...
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Bidirectional jerk motion on a stopping vehicle

A stopping vehicle (say a car) has an apparent retardation (which may/may not be constant in magnitude) when force via brakes is applied. I travel by subway trains, and I noticed an odd phenomenon. ...
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When Does Mass Matter? [closed]

I have been trying to wrap my head around this idea for a month or so, and I am not really sure how mass plays into the velocity of a moving body. I have not taken physics in a while, but one thing I ...
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Does a wave have inertia?

In de Broglie hypothesis, particles have wave nature. The question is does this wave have inertia? If so is it represented in the corresponding wave equation?
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A silly, but confusing, question about the Inertia coeficient of second law and inertial mass

My question is about the inertia coefficient on second law. To be more specific I have doubts on the notation. 1) Some authors show that the force $F$ is proportional to mass $m$ times acceleration $...
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What is the connection between inertial/gravitational mass and relativity?

In Einstein/Infield 's The Evolution of Physics (32-35) the authors establish that inertial mass and gravitational mass are the same and then connect this to relativity.Throughout these pages I was ...
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A trio of spinning marbles

My little brother showed me this devised act in which he stuck three marbles in a triangular pattern When he spun any of those marbles, the triplet would first rotate normally, but moments later, ...
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Why does overcoming inertia depend upon time?

When a paper over a glass is pulled suddenly, the coin over it falls to the water. But on pulling it slowly, the coin gets pulled along with the paper. Why does the coin in the former case not feel ...
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Moment of inertia of the sphere [closed]

My teacher has written (I is the moment of inertia of sphere) : I (about x axis) = I ( about y axis ) = I( about z axis) =I then the summation of them is equal to 3*I = 2*I(c) where c is the center ...
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Inertia for a large mass (in outer space)

I understand that an object doesn't need a force to keep moving; that it will keep moving indefinitely in that direction at that speed. My question though is: if you were in outer space, where ...
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Rotating the bucket in circular motion without spilling water

In the bucket experiment when the bucket reaches the top of the circle why will it have a normal force acting on the water downwards? Doesn't normal force oppose any other force? There is no force ...
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Why bikes are made lightweight?

From Wikipedia: The most important characteristics about a racing bicycle are its weight and stiffness. If I understand correctly, the greater the weight of the body, the greater its inertia (...
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Does a box containing photons have more inertia than an empty box?

A box containing photons gravitates more strongly than an empty box, and thus the equivalence principle dictates that a box containing photons has more inertia than an empty box. The inescapable ...
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Centripetal and Centrifugal force

If water stays in a pail of water that is whirled around a circular path, the water stays in the pail. But is it because of centripetal force or inertia? I'm getting confused by all the different ...
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1answer
120 views

Moment of inertia and gravity

Would the objects have moment of Inertia if there was no gravity? Because imagine a bar, if I put my hand at the center of the bar and rotate it, it would be easier than rotate the bar picking one ...
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What is the meaning of “moment”?

What is the meaning of moment? I'm little confused about the word as there are some terms like moment of momentum, moment of mass, moment of force, etc. I want to know what exactly is meant by the ...
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What is the minimal G-force curve in 2-dimensional space?

Given two parallel roads, which need to be connected, what shape of curve would produce the minimum overall horizontal G-force(s) on travelers? Is it a $sin$ or $cos$ wave? Is it a basic cubic ...
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What is the relationship between potential energy and inertia?

It seems to me that the two are very similar! Potential energy seems to either explain, or partially explain, directly or indirectly, the law of inertia. I already know that bodies do not move because ...