Loading...

And this one here is the spot, you're right, it's the top of the tire. If you were to do the math on that, you check all the vector quantities of the tires that's moving, you would see that it all adds up. Because you drop to zero when it's touching the ground in order to maintain that, it has to gain some speed somewhere. So the top of the tire is twice as fast as the tires moving regardless of speed. And an experiment can find to get an idea how this works. If you had a bicycle, just drop in. If you had a bicycle, put a little chalk bar, maybe on the top of the tire or the wall of the tire at some point, and just anything that's been down the road. And just watch it, and just watch it. Go slow so you can actually see it's moving. And you'll see as the tire is rotating, you watch this little chalk bar come up. But as it gets to the top of the tire and it starts moving on, you'll see it's starting to move ahead of the bike. It's actually moving faster than the bike at that point. You'll see the chalk bar pulling ahead of the tire as it's rotating forward, faster than the top of the fender of the bike. So experiment. Try it. See for yourself. Try it on another fancy bike. Report your results. See you tonight. Alright, that's it. Thanks for watching.