@ #60 posted by brainologist
"but go ahead, tell us you were being sarcastic"

no need, I wasn't being sarcastic.

In physics, mechanical work is very specifically defined with units of Joules.

1 Joule = 1 Newton * 1 Meter.

1 Joule is the work done when an object is moved 1 meter by the application of 1 Newton of force in the direction of motion.

By it's very definition, work is independent of mass.

You correctly pointed out that F=m*a, but then promptly ignored "a".

If acceleration is constant, then yes, work is proportional to mass. However, if force is constant (as in my previous example) then acceleration is inversely proportional to mass, and work is independent of mass. See now?

@ #33 posted by t3knomanser:
"no, it's about work. Work is force * distance, and force = mass * acceleration."

So far, so good. Yay physics.

"More mass moved across the same distance is more work."

And here is where it falls apart. Take this simple example: Let's say Bob pushes a bicycle with 1 Newton of force, and Alice pushes a car with 1 Newton of force. After one mile, Bob and Alice have performed the same amount of work. See that? W = F*d. Work is independent of the mass of the object.

So, unfortunately, the rest of your conclusion is invalid. Seems a bit like "a little knowledge is a dangerous thing".

@ #9 posted by t3knomanser:
"Your body is far less efficient at turning fuel into energy than a car."

Please tell me this is a bad joke? Here's a quick comparison for you. One US gallon of gasoline contains about 31,500 calories. A person running a marathon (26.2 miles) consumes roughly 3,000 calories.

"Pound for pound, your car is definitely more efficient than you are."

Oh, I see. Something that is inefficient but really really heavy wins.

I stayed at a hostel in Polebridge, Montana, right next to Glacier National Park. When I arrived, no one was around and I just found a little note that read, "Make yourself at home, beds are upstairs. If you don't see someone before you go, please leave your money on the desk by the door."

(I did see the people running the hostel before I left)