Shutter speed

I want to learn how to do this. I want to master this photography skill. See that white car? it showed that its moving but the rest of the subjects in the picture stayed still. Same with the second picture. Hubby took these shots and he even taught me how to do this. I understood when he told me but now I forgot again, lol.

I like this type of photography. Looked real and simple. Hubby told me its all about shutter speed. Let me see if I can remember what he said. If you make the shutter speed number bigger than the shutter of the lens will go fast thus you will capture the object stay still. But if you make the shutter speed smaller, meaning the shutter will close slower and you will get below picture. Phew... its not easy! I cant even comprehend something as simple as that!

I'll check with him later if thats correct, hahaha.