Inertia Definition and 1000 Threads

If a beam's y-y axis lies in the plane of the paper, do I use Ixx or Iyy from sections table?

Hi, I have some troubles to understand the next step for the solution. If you need more informations, please let me know. 1. Homework Statement A moving vehicle of mass M is moving down an inclined plane of angle alpha with respect to the horizontal plane. What is the force indicated on the...

So is a Bike driver stable when the bike is running because the bike wheels has a certain moment of inertia about the horizontal axis ,which might alter(mi gets lesser) if the direction of the axis changes ? Thanks in advance

Homework Statement During the head on collision of a 1500kg car moving 20 m/s and a 2400 kg truck moving 12.5 m/s does the car move farther than, a shorter distance than, the same distance as the truck, or is this indeterminate with the given information. Homework Equations...

Hi, I need to calculate the moment of inertia of this flywheel so I can calculate the torque I need. T= I*alpha Attached is an image of the flywheel the cam follower that will be attached to the shaft (left shaft in this picture). When calculating the Moment of Inertia, what mass do I use...

Hi everyone, I am trying to find out the Moment of Inertia of a sphere which is all known to be 2/5(m)(r^2) I calculate this in 2 ways. One by triple integration and one by disk method. From the textbooks, moment of inertia should be in the form, dI = (r^2) dm, However, the textbook, University...

Homework Statement I am having trouble understanding the formula for Moments Of Inertia by direct integration. Homework Equations I understand the following (which is the definition) : $$ I_x = \int y^2 dA $$ $$I_y = \int x^2 dA $$ However come to application on a problem, my book doesn't...

Homework Statement Why does an object with a bigger mass(more inertia) accelerate the same as an object with a lesser mass(less inertia) when in free fall? Homework EquationsThe Attempt at a Solution

Hi! is there anyway to calculate inertia in 3d? for all forms, like we do in 2d, is it the same? https://upload.wikimedia.org/math/d/d/3/dd3b5877d05c86142f03703ac1c6562b.png

I am unable to find it.

Homework Statement Two spheres look identical and have the same mass. However, one is hollow and the other is solid. Describe an experiment to determine which is which. Homework Equations mgh= ½ m v^2 + ½ I ω^2 where I= 2/3 mr2 for a hollow sphere I=2/5 mr2 for a solid sphere The Attempt...

Homework Statement >Problem:<br>Find the Moment of Inertia of a circular disk of uniform density about an axis which passes through the center and makes an angle of $\dfrac{\pi}{6}$ with the plane of the disc. Homework Equations Moment of Inertia ($I$) is $$\int r^2dm$$ where $r$ is the...

Hello, Let me explain my question. We know from GR, that gravity is just something (planet, light, etc) following a geodesic path through distorted spacetime. But that's just because everything is still in motion from the big bang, traveling at the speed of its own inertia. So let's assume...

See image. It would be better if you can show me the calculation process. EDIT: the axis of rotation goes right through the centre of the cylinder. NEVER MIND! GOT IT!

What is the overall moment of inertia of many cylinders in contact, where each is rotated about an axis through its center of mass. For example, a set of rollers. (See picture)

I know the formula for moment of inertia is but there are I = MR^2 but there are also formulae for different objects as shown in the picture. So, how and when do you use I = MR^2 ? Just in case of (a)? Thanks!

The hoop has radius R. I used the same way to plot the axis for the hoop: ##l^2 = r^2= 4R^2cos\theta## since: ##r=2Rcos\theta## 2\rho \int_{0}^{\frac{\pi}{2}} r^2 r d\theta 2\rho \int_{0}^{\frac{\pi}{2}} 8R^3 cos^3\theta d\theta answer is \frac{32}{3}R^3\rho , and its wrong using the...

We know that the rotational inertia I of a certain object is I =∫r∧2 dm where r is the distance between the axis of rotation and the increment of this object that carries a mass dm. What confuses here is the following: Take for example a hoop of mass M and radius R. Integration theory gives...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >[/color] Hey, So I am not sure if this is in the right section but feel free to move it. We are conducting an experiment at school at the moment and are having difficulty understanding all the...

I am modelling the attitude dynamics of a satellite. The satellite has a reaction wheel in 1 plane to help control the attitude. There is significant debate about the equation for the net angular momentum of the satellite and what inertia tensors should be used regarding parallel axis theorems...

Looking at the image below, we have the function z^2=\frac{r^2}{a} yrevolving about y-axis. We know that y goes from 0 to "a". We also know the mass of the object (of uniform density). Do you think is my procedure correct? Do you get the same result?

Hi, I am a bit confused about the units of MI...I read that MI of rectangle is b*d^3/12,so unit is mm^4..Also i read in wiki that unit of MI is kg.mm^2... Both are correct,but why this difference is?

1. Material 2. Questions: a) (pink) Why does the author use two different values of inertia for the same slender rod ? The Attempt at a Solution [/B] a) I could assume that 1/3 is holding it at the end and 1/12 is holding it in the center. But it's not interchangeable because if I chose 1/3...

Homework Statement In the figure, block 1 has mass m1 = 450 g, block 2 has mass m2 = 530 g, and the pulley is on a frictionless horizontal axle and has radius R = 5.3 cm. When released from rest, block 2 falls 71 cm in 5.0 s without the cord slipping on the pulley. (a) What is the magnitude of...

Homework Statement What is the moment of inertia round the axis of a cylinder length L, mass M and a linear distribution of mass with the radius R, zero at the center. Homework Equations Moment of inertia: ##I=mr^2#3 The Attempt at a Solution The density ρ=kr. what is k? the total mass is M...

Homework Statement Show that the moment of inertia of a rectangular plate round it's diagonal, line B-B is equal to the one round a line parallel to one of the edges and passing through the center, line C-C Homework Equations Moment of inertia: ##I=mr^2## The Attempt at a Solution For the...

Homework Statement Calculate the moment of inertia of a cube of mass M and edges d round an axiz, z, that passes in the middle. Then calculate around an axis parallel to the z axis and passing on one of the edges Homework Equations Moment of inertia: ##I=\int r^2dm## The Attempt at a...

I did a simple experiment. I took a small block of copper (40g) and sensitive scales. First I cooled the block in a freezer (-2C) and checked its weight. Then heated it up to 300C in the oven and checked weight again. The difference in weight is well observed (4 - 5mg). Results are consistent...

Homework Statement A thin, uniform vane of mass M is in the shape of a right triangle, as shown. Find the rotational inertia about a vertical axis through its apex, as shown in the figure. Express your answer in terms of the triangle’s base width b and its mass M. Homework EquationsThe...

Homework Statement Determine the moment of inertia of the cross sectional area of the T beam with respect to the x' axis passing through the centroid of the cross section.(I'm attaching a diagram) Homework EquationsThe Attempt at a Solution Hi! I'm having a little trouble with this problem...

Homework Statement The profiled steel I above is topped by a " profiled C ". Determine the moments of inertia of the structure composed by the axes central x and y through its geometric center C. Picture representing the problem: Homework Equations Profiled C and I information: The Attempt...

Hi, new here, so I hope I'm doing this correctly. I'll keep this question as brief as possible, but it requires just a bit of setup. I'm not an engineer or physicist, but do have a more than decent layman's understanding. I've lately become fixated on the game of bowling (ten pin), and have...

Homework Statement What is the angular inertia of a disk (cylinder) with... Maximal radius, rmax = 10cm Thickness, h = 4cm density, d = 3g/cm3 rotational axis in its centre (like the axis of clock hand in a disk shaped clock) Please show and explain your procedure in finding the...

Homework Statement Two particles of mass m1 = 14 kg and m2 = 24 kg are connected by a massless rod of length 1.4 m. Find the moment of inertia of this system for rotations about the following pivot points. Assume the rotation axis is perpendicular to the rod. A) center of rod B) end of m1...

Force is something that causes acceleration... Inertia is something that opposes acceleration...Can inertia be understood as some kind of negative force prevelant everywhere in the universe? (Hope this doesn't get locked/deleted, these days one can't even think safely)

Homework Statement Three particles, each with mass m = 0.5 kg, are fixed on a uniform circular ring of mass M = 2 kg, radius a = 0.6 m and centre O, to form the corners of an equilateral triangle. What is the moment of inertia of this system? Homework Equations I = Σma2 The Attempt at a...

So the following question is attached (There is another thread with the same question but no solution to what I am asking on there) Now according to several solutions, apparently IYZ is equal to 0, and they reason this by saying that the geometry is symmetrical. However when looking at the...

Inertia is the resistance of any physical object to any change in its state of motion, including changes to its speed and direction. It is kind of counterforce which is resisting the change of speed. But when there is this counterforce which is at the same level as force causing the...

Homework Statement What is the Moment of inertia of rod about an axis inclined? It is given as ## \frac{ML^2sin^2θ}{12} ## but how? Homework Equations I know MOI for axis passing through center along y-axis as ## \frac{ML^2}{12} ## The Attempt at a Solution Shouldn't it be ## \frac{ML^2}{12}...

Hi, Is there a way to derive the moment of inertia of a sphere without using the M of I of a cylinder? In other words, is it possible to find a sphere's from scratch? Please include a derivation in your answer, unless there isn't one of course.

Hi, I'm wondering about the effect of the shaft flex on the impact velocity between the club and the ball. I understand that as I swing down the golf club, the shaft flexes and the club head lags behind. Near the end of the point of impact, the shaft bends forward. Intuitively, I would think...

I have a question about body inertness. Is moment of inertia is unambiguous inertness characteristic?

Homework Statement Hi all, I just had a quick question regarding a problem that I have to write a lab report on. The problem involves solving for the moment of inertia of a system that involves a pulley with a hanging mass attached to a spool that turns a flywheel. The solution is supposed to...

Homework Statement I am trying to work the moment of inertia for a) rotating rod, axis through the centre of the rod http://hyperphysics.phy-astr.gsu.edu/hbase/mi2.html#irod3 b) Solid cylinder http://hyperphysics.phy-astr.gsu.edu/hbase/icyl.html#icyl2 [/B] Homework Equations I = R^2 dM The...

I would appreciate someone's advice on the following question: "An airplane was moving in the forward direction on the runway when it suddenly stopped. When the airplane stopped, some passengers who did not put on their seat belts fell forward from their seats. Would a passenger of larger...

Homework Statement Homework EquationsThe Attempt at a Solution I assume the energy stored is = 1/2 (I) (ω^2) I (moment of inertia) is MR^2 since it's a hoop? or is it a solid cylinder? do we need to convert the rpm (revolutions per minute) to radians per sec?

Seems exist some relationship between the inverse of a matrix with the inertia tensor, looks: This relationship really exist?

Sorry to bring this question up again. @aridno provides a nice formula of the moment of inertia I about the centroid in https://www.physicsforums.com/threads/calculating-polygon-inertia.25293/ as: $$...

Homework Statement Homework Equations Kinetic Energy = 0.5 I w^2 v = r * w torque = Inertia * angular acceleration The Attempt at a Solution That's the problem. I have no idea where to start. I assume that the end goal is to find the angular velocity, and convert to linear velocity, but I...

I had a discussion with my friend. He took an icecream stick and told me that if the stick was held horizontally the stick would break easily but if you held the stick vertically it would be difficult to break the stick. He said that vertically the moment of inertia is more. My question is that...