The inertia of a particle or larger object is a measure of its resistance to move. When a body can be modeled as a particle, its mass determines its inertia. For a larger body which is rotating about a fixed axis the particle model is no longer appropriate and its reluctance to move is determined by a quantity called its moment of inertia. It is denoted as

**and SI unit is***I***.***kg$m^{2}$*The formula to calculate the moment of inertia is,

$I = MD^{2}$

Where

**M**is the mass

**D**is the distance from the axis of rotation

**Step 1:**Note down the given parameters from the question.

**Step 2:**Plug these given quantity in $I = MD^{2}$

**Step 3:**Calculate the unknown quantity

The problems of Moment of Inertia are given below:

### Solved Examples

**Question 1:**The mass of a bob is 10g and the distance between bob and axis of rotation is 35cm. Calculate its moment of inertia?

**Solution:**

Given measures are,

m = 10g = 0.01kg

r = 35cm = 0.35m

The formula to calculate the moment of inertia is,

$I = MD^{2}$

I = 0.01$\times0.35^{2}$ = 0.001225 kg$m^{2}$

**Question 2:**Mass and distance between an object and axis of rotation are given as 5kg and 10m respectively. Calculate its moment of inertia?

**Solution:**

Given measures are,

m = 5kg

r = 10m

The formula to calculate the moment of inertia is,

$I = MD^{2}$

I = 5$\times10^{2}$ = 500 kg$m^{2}$