# Moment of Inertia of a Mass

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

### Single Mass formula

$$\large{ I = m \; r^2 }$$

### Multiple Masses formula

$$\large{ I = m_1 \; r_1{^2} + m_2 \; r_2{^2} + m_3 \; r_3{^2} }$$

Where:

$$\large{ I }$$ = moment of inertia

$$\large{ m }$$ = mass

$$\large{ m_1 }$$ = mass

$$\large{ m_2 }$$ = mass

$$\large{ m_3}$$ = mass

$$\large{ r }$$ = radius

$$\large{ r_1 }$$ = radius

$$\large{ r_2 }$$ = radius

$$\large{ r_3 }$$ = radius