# 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!

373 questions
Filter by
Sorted by
Tagged with
408 views

### Do photons have inertia?

We all know the example where we say that a massless box containing photons has inertia, because the photons exert pressure of the inner walls of the box. But my question is about a single photon ...
59 views

### Question on Reynolds number using Newton's definition of inertial force and how to obtain the common expression for Reynolds number?

The concept of inertial force is traced back to Newton’s Philosophiae naturalis principia mathematica, The Principia, Newton. At the beginning of his book, Newton presents eight definitions forming ...
5k views

### Flying a drone in a moving car/airplane

Why does a drone fly with respect to the air in a moving car/airplane, but not in an elevator as shown in this clip: What Happens If You Fly a Drone In An Elevator? I understand that the drone will ...
66 views

### What are the “masses”?

I know there are three "masses". "inertial mass", based on Newtonian Mechanics "rest mass" and "relativistic mass", based on relativity Anyone can explain three ...
65 views

### What physical phenomenon causes racing bike to lift automatically after it fall down?

What physical phenomenon causes racing bike to lift automatically after it fall down? What causes it to travel further distance after it fall down? Please help me. Animation: YouTube link :https://...
53 views

### Inertial mass and gravitational mass [closed]

I would like to ask about gravitational mass. I know inertial mass is changing by motion (speed) according to $m=\frac{m_o}{(1-v^2/c^2)^{1/2}}$ And also that is inertial mass which sits in $E=mc^2$. ...
29 views

### Changing effective mass of electron using electric potential?

The Dirac equation for an electron in the presence of an electromagnetic 4-potential $A_\mu$, where $\hbar=c=1$, is given by $$\gamma^\mu\big(i\partial_\mu-eA_\mu\big)\psi-m_e\psi=0.\tag{1}$$ I assume ...
44 views

### What if inertial and gravitational mass were different?

It's well known and heavily documented that gravitational and inertial mass are identical. This has been experimentally tested to many digits of precision. But nothing I've seen ever describes how ...
136 views

### Does the Higgs field explain inertia?

As far as I understand it the Higgs field leads to the creation of rest mass for certain elementary particles but does it explain the phenomenon of resistance to acceleration associated with rest mass?...
247 views

### Does general relativity explain inertia?

As far as I understand it general relativity does not explain the origin of the inertial mass $m_i$ in Newton's law of motion $\vec{F}=m_i\ d\vec{v}/dt$ but rather it simply applies the concept to ...
5k views

### Is “Mass” really measuring unit for inertia?

Imagine if two objects of identical mass are under two different gravitational field,let's say two different planets (with Different value of gravity) both of the objects are of same mass,but we can ...
230 views

### Why do objects have inertia? [duplicate]

I was going through the chapter of "Newton's Laws of Motion", where I was introduced to the concept of inertia in Newton's First Law. I saw that all objects that have mass will have ...
92 views

### Are falling objects harder to push compared to objects at rest

While an object is still in the air falling under the influence of gravity, does it take greater force to push or steer it to the side compared to when the object is in a state of rest?
307 views

### Is inertia the same as centrifugal force?

My cousin told me that inertia is just a pseudo force that act on a thing, because he said that inertia is the same as centrifugal force. But when I search for the true fact in Google, I found that ...
431 views

### How do you apply each of Newton's laws to specific scenarios?

The 3 Newton's laws of motion are easy to be understood but examples citing which law caused it are so confusing - say a bullet fired from a gun - many people state it cause is 3rd Law - but I see all ...
131 views

### How to calculate heat loss of a building using thermal inertia

I need to calculate the amount of heat that is lost in an hour. I know the temperature of the building the (effective) temperature of the outside and the thermal inertia of the building. The building ...
561 views

### Confusion about an example of inertia related to bus

When the bus is stationary the passengers are also stationary. When the bus starts moving the part of the body (lower part) in contact with bus starts moving, but due to inertia the upper part remains ...
88 views

### Why lighter bottles stay on better rather than heavy bottles?

I was watching a Mythbusters video of them doing the table cloth trick and Adam says that the lighter bottle worked better. Don't heavy bottles (more mass) have more inertia and therefore should work ...
55 views

### Working principle of an accelerometer

I'm trying to confirm my concepts regarding inertia and accelerometers. Need to verify / correct my thoughts, which are as follows: Inertia is the property of matter to resist a change in its state ...
66 views

### Why can't we measure inertia? what are the applications of inertia?

why there is less importance for 'inertia' in school studies...does the concept of inertia is least significant nowadays? is inertia a measurable quantity? Is there any application of inertia?
193 views

### Why is Newton's First Law not considered a vacuous statement? [duplicate]

How did Newton come to postulate the law of inertia when every inertial body that he was considering was (by his own other hypotheses) being acted on by the force of universal gravitation. In other ...
220 views

### Moment of Inertia using centre of mass knowing distance and weight of rod [closed]

I know the mass, I know the center of gravity position. Can i use this to work out the moment of inertia of a rod. So my ruler is 30 cm long and I know its mass to be 11.8g I have some blu tac which ...
998 views

### How can energy have inertia?

How can energy have inertia? To my intuition, inertia is so closely associated with mass that my intuition says "Huh?" Indirectly by mass energy equivalence it works fine, for example: I have a ...
46 views

### Inertia and related quantities

I wanted to know what is a frame of inertai? Specifically, what does it mean by a frame? I know that inertia is the restistance to motion of a mass, a larger mass resists motion more than a smaller ...
26 views

### An expanding, sliding charged tube's self-imposed electromagnetic induction

If I have a simple cylindrical electrically-insulating tube possessing a net electrostatic charge and allow the tube to slide parallel to the tube's axis, that tube will possess electric currents ...
2k views

### Definition of mass

In high school physics, I was taught that mass was just how much "stuff" or matter there is in an object. However, now that I am learning physics again in college, I am taught that mass of an object (...
284 views

### Calculating end position from existing position, velocity, deceleration and time

I am writing a piece of software where the user can drag an element only on the x axis. When the user lets go of the drag while the item is in motion I can determine the x velocity and the current x ...
54 views

### Why won't a full laundry basket bounce?

I've noticed a curious behavior of my plastic hamper and laundry baskets. When they are empty tossing them more then a few feet from hip height (3 feet) causes them to bounce and tumble. Yet when they ...
62 views

### If the aircraft has no inertia, how will it move after losing power?

If the aircraft has no inertia, how will it move after losing power? I think because of the aerodynamic force, the aircraft stopped moving immediately. Am I right?
58 views

### What is the cause of motion in geodesic

The shortest or longest path in curved space between two points is geodesic . What about a body having no potential energy was put in geodesic near earth , what makes it move , May be it is about the ...
135 views

### Calculating new mass moments given change in CG and transformation

Given the mass moments of inertia about the CG of the body pre-rotation, and the new CG & rotation matrix1, how can I find the new mass moments about the body's new CG? My CGs are described as ...
545 views

### Should the coin be heavier or lighter in the coin drop experiment?

The Coin Drop experiment is a classic experiment used to demonstrate Newton's First Law of Motion. In this experiment, a glass is covered with a card and a coin is place on the card. The card is given ...
126 views

### Mass as worldline tension?

In Special Relativity, the equation of motion of a particle of proper mass $m$ is \begin{equation}\tag{1} \frac{d p^a}{d \tau} = \mathfrak{F}^a, \end{equation} where $p^a = m \, u^a$ is the 4-momentum,...
166 views

### Can momentum be considered as a measure of inertia of motion?

If inertia of motion is a body's tendency to be in motion then can momentum be considered as a measure to calculate that tendency to be in motion?
30 views

### How to calculate the tensor of inertia in this problem?

I have the following geometry for my problem: I'm asked to calculate the tensor of Inertia: \$\stackrel{\leftrightarrow}{I}_{O}=\left[\begin{array}{ccc}{I_{11}} & {-P_{12}} & {-P_{13}} \\ {-...
96 views

### What happens when the matter is not showing the property of inertia? [closed]

I am trying to imagine a situation when there is no inertia.
178 views

### How may the situation, when there is no inertia? [duplicate]

I want to know clearly the real concept of inertia.I have seen lot of definitions regarding inertia.But I could not exactly find real meaning of inertia.
284 views

### Why is it impossible to start or stop an object instantaneously? In what ways can a non-accelerating object move? [closed]

Why is it impossible to start or stop an object instantaneously? In what ways can a non-accelerating object move? I think this has to do something with inertia, but I am not exactly sure I fully ...
49 views

### Why are you accelerating yet remaining at a constant speed while going around a curve? [duplicate]

We have to write a rap in physics, and it has to answer a prompt he gave us on this packet. The prompt for the verse I am writing is: Pretend you are driving a car on the freeway going 65 mph. The ...
68 views

### Why does things travel in a straight line in inertial frames?

Why does physical entities travel in straight paths in a flat space-time and in geodesic in curved spacetime? Is it due to Inertia? If it is, then why does waves also follow the same pattern?
133 views

### Isn't inertia experience by person in moving bus is 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,...
355 views

### How would inertia work in an elevator?

If we imagine standing on a scale inside an elevator, the scale will project our weight. As the elevator starts to move downwards we will not start to move downwards immediately; because of inertia we ...
7k views

### What causes a rotating object to rotate forever without external force—inertia, or something else?

Someone told me that it is not inertia, but I think it is inertia, because it will rotate forever. In my understanding, inertia is the constant motion of an object without external force. Am I wrong?
70 views

### Mathematical model for transition from mass to energy put in layman's terms [closed]

Mass and inertia are interchangeable, but no intuitive explanation of mass being different for the various particles is known to me. The question I have is: since mass and energy are interchangeable, ...
1k views

### Weight and Inertia (are they related?)

R. Feynman wrote in his lecture (The Feynman Lectures on Physics: Chapter-9) "Weight and inertia are proportional, and on the earth’s surface are often taken to be numerically equal, which causes a ...
2k views

### Is there still no known origin of the law of inertia?

To quote Feynman at about the 21 minute mark of the first Messenger Lecture on The Character of Physical Law, ...that the motion to keep it going in a straight line has no known reason. The reason ...
78 views

### In zero gravity!

If spacecraft moving in a stable speed or acceleration suddenly stopped would an astronaut continue moving forward (such as a man in a train) ?
838 views

### How can a flywheel make engine run smoothly?

In the video Moment of Inertia Demo, a man states that moment of inertia will be higher if the masses are away from the axis of rotation. The engine take more power to spin the flywheel, because of ...