Rip: The Deadlift vs The Clean

[Mark Rippetoe]

The Deadlift vs The Clean | Mark Rippetoe

[asm44]

I liked this more technical article, but one minor thing stood out to me as confusing:

A clean must be accelerated in order to be racked on the shoulders – it must be moving fast enough to attain sufficient momentum (the product of the mass of the bar and its velocity) to continue upward

The momentum doesn't matter. The bar must simply be moving fast enough to continue traveling upward a sufficient distance to be racked. A very heavy bar could have a greater momentum after the pull than a lighter bar, but be travelling slower and hence not satisfy the velocity requirement to be racked, while the lighter one does.

[Mark Rippetoe]

True, but whatever the bar weighs it must have sufficient momentum AT THAT MASS to continue upward after the pull stops.

[Jr_Geezer]

And just to be super picky: "Acceleration is proportional to the force applied to the object and the mass of the object." really should be: "Acceleration is proportional to the force applied to the object and inversely proportional to the mass of the object."
F = ma, therefore a = F/m
The interpretation and explanation of what's happening are of course 100% correct, just that minor quibble.

[Mark Rippetoe]

And just to be super picky: "Acceleration is proportional to the force applied to the object and the mass of the object." really should be: "Acceleration is proportional to the force applied to the object and inversely proportional to the mass of the object."
F = ma, therefore a = F/m
The interpretation and explanation of what's happening are of course 100% correct, just that minor quibble.

Noted.

[stef]

And just to be super picky: "Acceleration is proportional to the force applied to the object and the mass of the object." really should be: "Acceleration is proportional to the force applied to the object and inversely proportional to the mass of the object."
F = ma, therefore a = F/m
The interpretation and explanation of what's happening are of course 100% correct, just that minor quibble.

"Propotional" doesn't specify - it applies to either relationship. Clarification for someone not aware of the equation or severely math-challenged would mean using both directly proportional and inversely proportional.

[Shiva Kaul]

Proportional means positively linear, so Rob gets his "I showed Rip!" sticker. Acceleration is monotonic in mass, though.

[JFord]

Clarification for someone not aware of the equation or severely math-challenged would mean using both directly proportional and inversely proportional.

The reason this is a perfect response to the issue is that I thought this the instant I read the thread. In 2015 when I took the seminar, (and as a fellow nitpicker like the OP) I asked Mark almost the exact same question and got roughly the same answer as he gave here.

We talked about this in a less public setting during the seminar and it’s very clear the Mark understands physics and is familiar with F-MA and Newtonian mechanics. The word momentum has different meanings to the layperson who frequently could care less about physics!

Proportional means positively linear, so Rob gets his "I showed Rip!" sticker. Acceleration is monotonic in mass, though.

Only if this were a physics forum which last I checked it isn’t (and this comes from someone who totally geeks out on physics). Pedagogy over precision or to paraphrase Jeremy Bentham, “The greatest good for the greatest number.”

I know. Show-offy. I’m insufferable.

[Jr_Geezer]

My apologies for being an overly pedantic asshole (note the use of "super picky" and "minor quibble"). When I read the quote in question, I was taken back to when I was working on my physics degree, where, if the professor said "A is proportional to B and C", we would all write the equation as A = BC. And, as I said, I'm an overly pedantic asshole.

Of course it absolutely goes without saying that Rip has a deep understanding of the physics involved here; I feel silly having to even write that.

[JFord]

My apologies for being an overly pedantic asshole…

I hope you don’t think that I think of you that way! I’m incredibly geeky and if you actually clean then by definition, you’re way less of a nerd then I am.