# 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!

280 questions
2k views

### 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 ?
371 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 ...
243 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 ...
136 views

### 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 ...
131 views

### 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. ...
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 ...
474 views

285 views

### 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 ...
54 views

### 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, ...
126 views

### 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 ...
189 views

### 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 ...
146 views

### 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 ...
8k views

### 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 ...
45 views

### 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 (...
3k views

### 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 ...
230 views

### 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 ...
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 ...
3k views

### 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 ...
54 views

### 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 ...
3k views

### 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 ...