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Galileo's experiment


cyruseternity

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Taja - try and be a bit more precise with your questions. You are asking members to help out - so the least you can do is write accurate and consistent questions

 

 

 

... change in velocity with distance is not constant, ...

 

...velocity decrease ...

 

So is it velocity or change in velocity (which we call acceleration) which decreases with the length of time the object has been falling?

 

Strange has provided a link for "change in velocity" diminishing - and frankly I cannot think of an everyday circumstance in which velocity will decrease during a fall

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No, it's not air resistance. The question is asking just what it says.

 

What is being described is that dv/dx gets smaller. As the object falls, its speed increases linearly with time, since v = at for constant a. Let's approximate the acceleration as 10 m/s^2. After 1 second the object is moving at 10 m/s and has dropped 5 meters. The change is speed per length is 2 m/s per meter. After 2 seconds the speed has increased another 10 m/s and it has dropped an additional 15 meters, so the change in speed per length is 0.67 m/s.

 

IOIW, speed increases linearly while distance increases quadratically. It's pointing out that a = dv/dt, not dv/dx. In a world before Newton, one might be tempted to think the latter might be true and insist on that because of logic or other philosophy. Galileo is pointing out that it's wrong.

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