Another indication of the sad state of scientific/technical knowledge in the US

As if another one were needed.

On CNN Headline news there was a story about roughly 270 Japanese school children plus 125 parents towing a jet airliner with a rope.

The announcer proudly announced that this worked out to a pull of 1/2 ton/student-parent.

I am not sure I am following. A nearly empty 747 weighs about 400,000 pounds. There were 395 students and parents. That does equal a pull of about 1000 pounds per student or parent. A 747 is on wheels and pretty well balanced so that is completly possible. A couple of people can easily pull or push a car that weighs several thousand pounds.

Or did I miss something completely?

I think that the OP means that the force being applied (the “pull”) is not meaningfully or accurately measured in this way.

I was wondering if it was something like that. However, people often talk about the hauling or pulling capacities of their vehicles in this same way.

Let me see if I understand. If you divided up the plane and each person pulled their part separately, each person’s section would weigh a half a ton. However, the force being exerted would depend only the friction they had to overcome. As Shagnasty points out, it was on wheels, so the friction, and hence the force exerted by the people, was much smaller than it would otherwise have been.

Right?

Yes, Shagnasty, it’s vital to realize that they are not lifting the weight of the airplane. If one stops to think a little, one realizes that neither students nor their parents can pull with 1000 lb. of force.

Was my point just made?

They have those strong man competitions on ESPN 8 (The Ocho!) where these guys pull semis and buses and other large vehicals.

I’ve pushed cars by myself.

It’d help if we knew the announcer’s exact wording.

“That is 1/2 ton for each person.”

Well, how would you word it so it doesn’t sound like the people were wasting their time? “Well Bob, if you averaged all the weight they had to pull it would be 1/2 ton BUT it’s actually only the friction on the wheels and bearings that they had to overcome, therefore these people should’ve just patted themselves on the backs and not wasted all our precious time with this horrible ‘real people’ story! Now on with the sad story about the kittens in the hurricane!”

Yeah, I’m bitter.

So he neither equated it to lifting that weight, nor described it as the force exerted? I see no problem here.

I wouldn’t talk about how much force each person exerted. Just watching all of those people lined up and pulling the airplane would be enough. With TV pictures announcers don’t need to talk nearly so much and they certainly don’t need to pass out bum information when they do talk.

The situation obviously is worse than I thought and has spread to other countries.

Because in no way is it 1/2 ton for each person. The force needed to pull the plane is equal to its weight (well, technically the normal force from the ground as a reaction to the plane’s weight, but whatever…) times the frictional coefficient of its wheels on the ground. That force is going to be a lot less than 400,000 pounds.

This site places the coefficient of rolling friction between hard rubber and concrete (I am assuming it was concrete, someone correct me if i’m wrong) at 0.01-0.02. Using the large estimate, the frictional force the people had to overcome was only (0.02)(400,000 lbs) = 8,000 pounds.

8,000 lbs/395 people = ~20 lbs each.

Twenty pounds. Sounds a lot less impressive than 1000, doesn’t it?

To reinforce the mundane and pointless, in order to get started rubber of the tires has tobe deformed by pulling and I think the starting force would be more than computed above. However, once the plane is rolling the inertial would do the deforming and 20 lb./person might very well keep it going.

I find it interest that one poster took the Karl Rove approach that since the announcer didn’t actually say explicity that each persone was pulling 1/2 ton there’s no problem. And another took the position that in order for an announcer to make something impressive the use of false information was OK. Sounds like a description of TV news to a T.

Yeah, you’re right, they would have had to overcome the static friction of the stationary tire, but i still can’t imagine that equating to more than 100 lbs per person, which works out to a coefficient of friction of 0.1, which is almsot certainly much larger than it actually is. 0.1 for even a stationary wheel is huge.

So I agree that all the reporter needed to say was how they came together to do it, it shows the unbirdled tenacity of the human spirit, blah blah blah. No need to try and make it seem more “dramaitc” by pulling some number out of your ass that isn’t even close to accurate.

The problem is that everyone is agreeing that no one exerted 1000 lbs. of force and yet we don’t think that is a bad way of phrasing it. You are stating that people are so stupid that they believed that the kids/parents were exerting 1000 lbs of force a piece. I don’t see it that way. If you loaded up a cart and filled it with 5000 lbs of material, dared me to “pull” it, I would be right to say that I “pulled” 5000 lbs.

The point is that “pull” is not a standard of measure. It only means that you moved something that weighed that much.

No, everyone is not agreeing that the announcer didn’t choose a bad way of phrasing it. (Or, stripping out the double negatives, I agree with the OP’s point.)

Even if there were no friction, they would have to exert some force to get it moving. In the sense that it takes more force to accelerate a heavier plane at the same rate as a lighter plane, the mass of the plane is a factor of interest. Saying “That is 1/2 ton for each person” is not technically wrong. He didn’t say the force was 1/2 ton per person.

How about “each person pulled 1000 lbs of plane”?

Would have been cool if the news casters explained what was happening, as bouv did, no? It’s still hella cool, and you get the added benefit of showing how things work in an accurate manner. I think that’s the sad part. It’s pretty impressive the way friction works; they could have based the story on that, as demonstrated in the hella cool and dramatic way it was, i.e., people pulling a plane.