1basic concepts

This chapter explains the basic concepts we’ll be exploring as we build. Note that it aims for strictly practical knowledge. Its goal is to get you acquainted with the laws of physics involved in building working LEGO mechanisms, not to cover everything a practicing engineer or physicist needs to know. So let’s get started with the basics.


Speed describes how fast an object moves. When you think of speed, you likely think about the distance a vehicle can travel within a certain unit of time. We call this linear speed, and we will be measuring it in kilometers per hour (kph).

But there’s another type of speed, called rotational speed, which tells us how fast an object rotates. We’ll need to understand rotational speed, as ...

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