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## AP®︎/College Physics 1

### Course: AP®︎/College Physics 1>Unit 2

Lesson 1: Newton's first law

# Mass and Inertia

Mass and inertia are interconnected concepts. Inertial mass is the property of an object that determines how its motion changes when a force acts on it. Inertial mass and gravitational mass are distinct concepts, but are experimentally verified to be equal. Created by Sal Khan.

## Want to join the conversation?

• so is the SI unit of inertia kg?
• The best way to think about mass is to think about it as inertia. The SI unit of mass is kg so in a way kg is a unit of resistance to a change in motion. However, I would recommend thinking of kg as a unit of mass just to keep everything conceptually clear. Hope this helps!
• What is resistance to acceleration?
• Resistance to acceleration basically means how hard it is to move something. More specifically, it’s how hard it is to change an object’s velocity.
• I was doing some research and I found out that there are two types of Gravitational mass: Active and Passive Gravitational mass.
What is the difference in between them and how do you measure them?