Question

Can anyone please explain what is moment of inertia?

Answer 1

moment of inertia denoted by I

Answer 2

What is its definition?

Answer 3

if a body of mass m circulating around a circle of radius r then the moment of inertia of that body will b
I=mr^2

Answer 4

I also read that formula. But can you please explain what does it represent?

Answer 5

What information does the moment of inertia of a point give?

Answer 6

moment of inertia is larger then the point mass resist to rotate

Answer 7

Is it like inertia of an object? If inertia is more then it is difficult to move the object.

Answer 8

Why does moment of inertia depend on radius?

Answer 9

need more torque to rotate a body of larger moment of onertia

Answer 10

suppose we're interested about finding what is the kinetic energy of rotating disc
let's see first what is KE of small mass element m:
the KE is simply:
\[E=\frac{ 1 }{ 2 }mv^2\]
It's more convenient to write velocity as \[v=\omega r\]
because omega is everywhere constant no matter which mass element yu choose, and r is the distance from origin.
so KE is now:
\[E=\frac{ 1 }{ 2 }m \omega^2 r^2\]
To find all the Kinetic energy we must add up each element thus
\[E_{total}=\frac{ 1 }{ 2 }\omega^2\sum_{}^{}mr^2\]
and \[I=\sum_{}^{}mr^2\]
is the moment of inertia

Answer 11

need more torque to stop a rotating body with larger moment of inertia

Answer 12

Is there any formula linking torque and moment of inertia?

Answer 13

ya it has

Answer 14

\[\tau= I \alpha\]

Answer 15

alpha being the angular acceleration

Answer 16

torque=moment of inertia * angular acceleration

Answer 17

I also read something about moment arm... What is it?

Answer 18

its a distance

Answer 19

its a perpendicular distance

Answer 20

its really the r sin theta the perpendicular component

Answer 21

perpendicular to what?

Answer 22

to force

Answer 23

u hv to draw a line frm a point of circulation to the line of force

Answer 24

I think force x moment arm gives torque.
So unit of torque should be joule (energy = force x distance)
Why is it Nm?

Answer 25

its not joule

Answer 26

its N.m