Treadmill Physics Questions (Similar to Airplane Question)

I must admit that in the days when I first dreamt up this thread, I doubted my assertion about lack of inertia and momentum was correct. Still since I was having trouble visualizing it (like conundrum) I was hoping to get some good discussion out of it.

Now after visiting this board for more than 6 years, I am proud to finally say I have started a thread that lasted more than 10 posts. I have reached the 100 mark. I'd like to thank letsrun for this opportunity and also the Airplane Treadmill Thread for allowing me to see what makes the letsrun-poster click. Hopefully this will be the start of a long thread starting golden age.

I think the thread is concluding soon thanks to thoughtful explanations, but I'd like to thank you all for being part of my first century. This is truly a great accomplishment.

Conundrum wrote:

No one has convinced why the block on the treadmill wouldn't continue to move if the belt was stopped abrutly when it has the same momentum.

First, no one would contend that steady state running is just like running on a treadmill that abruptly stops. I'd have dropped this thread except for running on a hotel treadmill this morning that did that a couple times and I soon gave it up before I got hurt.

Second, you've accelerated (decelerated) the treadmill running surface in your thought experiment which affects momentum. In fact you've accelerate the treadmill belt to the singular point where it instantly has zero relative velocity/momentum. Keep in mind the following.

1) momentum = mass x velocity

2) velocity is a relative quantity, that is, it is the vector difference between the velocity of any two objects that is relevent to their interaction

3) changing the velocity of one has the same effect on their interaction as changing the velocity of the other

It seems everyone is forgetting the fact that the belt is powered by a motor and running harder or slower has no effect on the power applied to the belt thus allowing for no additional build up of power or momentum. If the treadmill were to have a weighted belt on pulleys with no motor then momentum would be possible. There may be short bursts of momentum (life falling to the end of the treadmill and catching up) but no sustained momentum.

I have always believed running on a treadmill is more difficult than running in good level outdoor situations.

Whoa, resurrected old thread. Skimming through all this again it's a kind of sad commentary of the quality of high school physics classes that there are so many misconceptions about really simple principles :/

Haha I didn't realize how old the thread was. Still a fun argument.

From a purely newtonian perspective they are equivalent. How can people not see this? Probably didn't get an A physics in college.

I guess athletes really are dumb

What about the physiological effects due to a disparity in perceived effort?

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