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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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, (...
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Split moments of inertia into vectors - Right thing to do?

Let's say that we have the moment of intertia: $$J = mR^2$$ And the mass $m$ is on the $(x, y)$ position. Can I say that moment of intertia is then: $$J = mR^2 = m\sqrt{x^2 + y^2} ^2 = m(x^2 + y^2)$...
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What units is the moment of inertia for a point mass?

What are the units used in the integral equation for the point mass moment of inertia. Specifically what are the units of the double integral over a region R of $r^2· \rho· dA$, where $r$ stands for ...
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Why does a bowling ball roll down faster on a slope than a tennis ball, yet both hits the ground at the same time if they're dropped from the rooftop? [closed]

If a tennis ball and a bowling ball are dropped of a rooftop, they hit the ground at the same time. But if they are rolled down a slope, the bowling ball rolls faster. Why?
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How would I move if I grew by a factor of 3 in each physical dimension?

Suppose, for the sake of this thought experiment, I am structurally identical to an average human, with the only difference being that my body is scaled in all directions by factor of 3. This would ...
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Does free-fall imply that it is impossible to quantize gravity? [closed]

I will start by stating that I realise that there already exist questions on the compatibility of GR and QM (e.g. here) but my question is different. In this essay the following argument is made (pg ...
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What causes a particular object to have a tendency to go outwards in circular motion when the centripetal force is inwards to the center [duplicate]

Like a circular bead with a thread passing through it and the system being rotated . It can't be centrifugal force as it is pseudo only and has no existence when we are already in an inertial frame ...
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A Conceptual (philosophical) doubt on equivalence principle

The reference is: Elements of Newtonian Mechanics by J.M. Knudsen; Springer; page 108 to 113. My doubt is about the significance of the apparent distinction between Gravitation and Inertia. In ...
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Question on Inertia [closed]

I'm trying to get the concept right. If an object is accelerating in a straight line, with no opposing forces acting on it, will it continue to accelerate forever due to its inertia?
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Avoiding inertial affects by accelerating larger mass in 2 body system

Suppose two bodies S and L are in proximity (asteroids say). L is substantially larger than S. For simplicity, let them initially have negligible angular and linear velocity. S will begin to fall ...
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How did Newton prove the equivalence principle with pendulums?

I know pendulums may be equivalent to a free fall but I would appreciate any further explanation for it.
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Why doesn't a test charge placed in an electric field, trace out the same path as the electric field lines?

Consider for example a positive charge placed between a positive charge and a negative charge. Initially the test charge is placed closer to positive charge. Why is path followed by the test charge ...
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1answer
83 views

Is the inertia of a mass depended of his speed?

If a ball (10 kg) falls from a height of 10 km towards an (air free) planet with an acceleration of 10 m/s² then it gains every second in speed. But is the inertia of the ball getting every second a ...
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328 views

Does horizontal inertia affect the time it takes something to reach the ground?

I am new to physics. I’m confused about how an bullet shot horizontally would land at the same time with as a bullet dropped vertically (ignoring air resistance and the curvature of Earth). Having ...
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1answer
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Global momentum of a closed universe [closed]

In a universe: with 2 spatial dimensions closed (that loop on itself) with local positive and negative curvature with no attraction and no repulsion with particles randomly created by pair in the ...
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Does orientation matter when calculating inertia?

Two cylinders having the same mass, radius, size, shape and angular property are both rotating. Does this two identical cylinders have the same inertia despite their orientation?
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Using a gyroscope to get to space

Theoretically, if you could get an inertial mass or gyroscope spinning fast enough while on the earth' s surface, then as the earth turned would it continue to travel in a straight line and therefore ...
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What stops a projectile from going forward endlessly?

What stops a projectile from endlessly flying forward? Excluding gravity since it's an obvious one. Wind resistance is something that would eventually stop the projectile, anything else? Other that ...
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Ball inside an accelerating frame

Why does a ball inside a moving bus at rest start moving backwards when the bus suddenly accelerates? Also does the moving ball have some acceleration? This is my theory: Initially the bus and the ...
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Why are mass and the moment of inertia additive?

I have previously wondered about why mass is additive; i.e. the translational kinematics of some bodies can be determined by considering them as a single body with a total mass equal to the sum of the ...
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Does the Earth keep spinning because of inertia?

I understand that the earth continues to rotate about its axis because the angular momentum is conserved. (Am i wrong?!) But, I have seen quite a few sources cite that inertia is the reason why the ...
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Does it make sense an inertial mass dipole moment for massless particles?

Electric and magnetic dipoles exist in nature even with zero net electric and magnetic charge Electrons have a unit of charge, about $10^{-31}$ kg of inertial mass, zero electric dipole moment, $\...
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Does law of inertia has anything to do with speed of light?

I am not physics student so please pardon me if this sounds silly because I might be mixing irrelevant things here and I am not even getting how to ask my question. My main question is, does light ...
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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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391 views

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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284 views

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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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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521 views

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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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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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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206 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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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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