I was driving along Route 30 today from York to Lancaster and had just crossed the Susquehanna River when I came up behind a truck with a flat bed carrying a whole load of hay bales. As I passed him going 55 mph, I noticed that all the bales were losing short pieces of straw due to motion of the vehicle. An idea sprung upon me and I wondered how far the truck could get before all the hay would be blown away. I did some short research and found that an average range of a smaller, square bale of hay can weigh anywhere from 70-100 pounds. So the average is right around 85 pounds. I also reasoned that each small piece falling off is no more than 2-3 inches long. Guesstimating that one of these 2-3 inch long pieces of straw weighs 1/6 of a dollar bill, so 1/6 of a gram…the average lost piece of straw would weigh .167 grams and .000368 pounds. The truck was carrying about 30 of these 85 pound bales. If the truck lost an average of 10 of these pieces every 5 feet, how many miles could the truck go before all the hay would be blown away? I think I have the right answer but I don’t want to give it away…
(30 • 85) lbs / (10 • 0.000368 / 5) lbs/ft = 3,464,674 ft or 656 miles.
Is this a trick question?
No tricks, that’s exactly what I got. I guess many of the puzzlers are tricks though and this one was possibly too easy! I tried to be realistic with the measurements although the weight of the 2-3 inch piece of straw is probably much less considering the difference in thickness of a dollar bill and a piece of straw. I couldn’t the mass and length of a piece of straw so I was forced to guess. It’s only a guesstimate as well of how many pieces actually fall off every 5 feet…this could drastically change the answer. I guess in addition to this…How many bales of hay would a truck need to be carrying to have any left on the truck, if the truck was traveling from Lancaster, PA to San Diego, California. The mileage between the two places is 2672 miles.
“No tricks, that’s exactly what I got.”
Brilliant minds work in synchrony!!!
I enjoyed your puzzler.
Ah-why don’t they put tarps on the bales?
Because in reality, after the loose ones blow off, the tight ones stay in place.
The pieces do not blow off at a linear rate. It’s more like radioactive decay. So the best you could do is calculate the half life of a bale.