Today I noticed a "chained pen" (assuming that's what it called; though the "chain" was a series of metal beads connected by an apparently-metal string) with the pen and chain removed from its holder but still connected to each other.

 

I then proceeded to pick it up and, while holding the pen, spin around the "chain" in a circular motion. (Sort of like a standing wave, except instead of up and down it goes around and around... heh, that rhymes.)

 

I noticed that the faster I spun the "chain" the more of a "pull" it felt like there was on the pen... anyone here know what this is?

That's the inertia of the chain. Objects at uniform velocity (like flying in a straight line at constant speed) remain so unless a force acts on them. In order to make it spin in a circle, you have to constantly accelerate it towards the center (the pen). This requires you to exert a force. In return, the chain exerts an equal and opposite force on you. That's what you're feeling.

That's the inertia of the chain. Objects at uniform velocity (like flying in a straight line at constant speed) remain so unless a force acts on them. In order to make it spin in a circle, you have to constantly accelerate it towards the center (the pen). This requires you to exert a force. In return, the chain exerts an equal and opposite force on you. That's what you're feeling.

Ah, right, centripetal acceleration...

 

... so basically, because the pen is what keeps the chain accelerating towards the center, the pen pulls on the chain, and by Newton's third law the chain is as a result pulling on the pen?

Ah, right, centripetal acceleration...

 

... so basically, because the pen is what keeps the chain accelerating towards the center, the pen pulls on the chain, and by Newton's third law the chain is as a result pulling on the pen?

 

Yes. You pull on the chain, the chain pulls on you. The chain pulls on the pen, the pen pulls on the chain. F = mv^2/r, so as you spin it faster, the force you must exert on the pen increases. If you spin it fast enough, the chain will not be able to exert enough force and it will break.