# Introduction

“In physics, we try to simplify things, to make things a bit easier Miley.”

“I like easy ,” Miley retorted.

It is convenient to consider any mass as a single particle with a mass concentrated at a single point, known as the center of mass. Conceptually, the center of mass is the point at which there is no net moment of inertia (i.e. rotational inertia). If mass has a constant density, its center of mass conincides with its geometric center.

Center of gravity is where we also consider gravity. If there is uniform gravity, center of gravity and center of mass coincide.

For instance, we can calculate the center of mass for you Miley, which is essentially your “center”. The reason why it may not be your geometric center, is because different parts of your body may weigh differently. I’ve put a red dot where I calculate this to be! Note this will be inside your body…

Miley, note my estimation is closer to your heart than your waist, because your legs and lower body are lighter than your upper body.

“It really brings a new perspective to ‘finding your center’,” Miley noted.

#### Jeremy Shum

Shum interweaves science concepts with a sentimental storyline, to engage young folk, and deliver moral maxims. He holds a Bachelors in Laws, Commerce (Accounting), a Cert IV in Training & Assessment, and a Cert IV in Small Business Management.