Dynamometer

"Do you know what a dynamometer is?"
About twenty minutes later I was inside of a car garage, speaking to my Dad's friend whom I knew before from soccer but felt I was meeting again for the first time. They spoke in Farsi and I listened as I understand much more than I can speak.
We walked through the back door and made our way to a big metal machine on the floor. My Dad pointed at it and told my that is what a dynamometer was. He said the front wheels, what drives the car, is what goes on the part of the machine that spins and spins the tires.
"So when I say someone is spinning their wheels, but not going anywhere, you know what I mean. The car is going really fast, it can go up to 100 miles per hour, but it just sits on the machine and all that moves are the front tires and they just spin around."
Dynamometer