Does the piston ever stop moving in a running engine?

[xxChrisxx]

Is the very bottom of the piston where it connects to the crankshaft considered the piston, or is that considered the push rod?

Thats called the connecting rod or conrod for short.

You'll have to forgive my complete ignorance of physics, as I have not even taken a single class, but it seems to me that the top of the apparatus (the piston)- moving consistently "Up & down," obviously must stop to change directions.

You'd think it was obvious wouldn't you.

However, as it's on a pivot, the "rod," (if that is considered part of the piston) does not stop moving; ever. It must move continuously as it's connected to a continuously moving crankshaft.

It's not counted as the piston. You are right in both cases. piston goes up and down, conrod up down and round.

That is, until gas is $8.00 a gallon and you can't afford to drive the Hot Rod El Camino anymore.

In the UK petrol almost is that! It'a about £4.20 a gallon, so that's about $7

 

[MacLaddy]

Well groovy. I think that about sums it up.

No wonder y'all drive Mini's... This petrol addicted society would crash if gas were that expensive. (watch, you'll see it next year)

 

[GSXR1000]

Unless the lower rotor blower puller is out of balance the piston can never have instantaneous velocity. Unfortunately there is no such thing as a naturally aspirated internal combustion engine that can run with the lower rotor blower pulley out of balance thus….. the piston must stop moving at
TDC as well as BDC!

listen to FRED!

 

[Lsos]

The piston never stops moving. It instantaneously changes direction.

Instantaneous velocity and motion are not the same thing.

Was this actually said? I couldn't believe it, so I searched the entire thread and I guess all this poster's posts were erased?

I thought the argument was about quantum effects or frames of reference, in which case at least it would be annoying, but not necessarily wrong. But here it was just a simple case of a guy not knowing what he's talking about.

As for the quantum effects and frames of references...there's certain reasonable assumptions that must be made when answering a question like this. The assumptions will vary based on the wording and the context, but in this instance, throwing in quantum effects, relativistic effects, and mixing it with the expansion of the universe is NOT reasonable, and will simply defeat the purpose of the question. That, or it's just a case of arm-waving by someone desparate for attention.

If we were to give any thought to these arguments, it would lead to the possiblility that when I got into my accident, someone could testify against me that it was MY fault because I was going 60000mph...clearly over the speed limit.