I recently had an exam with the following logic problem in Oceanography. It apparently doesn't have anything to do with Oceanography, but rather Physics or Mechanics, I don't really know. It was only for bonus, so I guess the professor is allowed to ask whatever he pleases. Anyway, it is really togging at my brain, and he refuses to answer the question until the end of the semester (no one in class answered it correctly). So here it is:

 

A car is traveling 60mph; a part of the car is traveling 120mph, and another part is traveling 0mph. What are the two parts?

 

Any help would be greatly appreciated as I'm starting to lose sleep over it. Thanks in advance.

The topmost point of any of the wheels is moving 120mph. The bottom most point of the wheel (the bit in contact with the road) is stationary, relative to the road.

 

It's easier to imagine if you think of a tank track. The top part of the track must be moving forward at twice the speed of the tank, relative to the ground, whilst the bottom part is stationary, relative to the ground.

You talk to your girlfriend for ONE second, and someone answers the post. I tell ya...

 

BUT as the tires are elastic they won't likely be going exactly 120 or 0.

Glider, thank you so much. That was along the line of what I was thinking. I was imagining it had something to do in parallel to CDs. Where the outer edge of a CD spins faster than the inner edge, but I couldn't put the 0mph part into the equation. I kept thinking of the outer tire to its relationship of its axel or hub. Thank you once again!

Skye said in post # :

BUT as the tires are elastic they won't likely be going exactly 120 or 0.

 

The bit in contact with the road wants to be doing exactly 0 in relation to the road, or you is gonna wake up with a crowd around you after you hit your first corner. This being the case, the topmost point wants to be doing exactly twice the speed (of the vehicle) in the opposite direction, or your tyre will rip itself apart and once again, you'll wake up in a strange place among strange people (an unnerving experience, trust me).

I`m with Glider 100%, it represents the only logical answer without going into the weird stuff.