A fully loaded M35 2½-ton diesel fueled cargo truck, 7m in length, mileage 4,7 km/L .Carrying US military equipment is about to cross a 5.3 Km long bridge. The bridge is not in good condition and if a truck with its cargo weighing more than permissible limit passes then the bridge will collapse. The checkpoint weighs the M35 along with its cargo and finds it just an ounce below the permissible limit.
After getting the nod M35 starts to cross the bridge with a constant speed of 36Kmph. When it crosses 1.8 Km, all of a sudden a rock pigeon weighing 25 grams less than a pound lands smoothly on the top of the M35 just 3.4m from its rear end.
WHAT will happen to the BRIDGE ? WHY ??
Lets consider M35 using diesel as a fuel. Density of diesel is 0.832 kg/L. Mileage of M35 is 4.7 k.m./L.
Now it travelled 1.8 k.m., so it loses 0.382 L diesel.
Now we know that,
V=0.382 L, density of diesel=0.832 Kg/L, so mass=0.318 Kg,
This is the weight of diesel lost.
Now add this mass with One Ounce (28 grams).
That would be 346 grams or 0.346 k.g. This is the free space.
If something sits on the truck having weight more than free space then the bridge collapses.
Weight of pigeon was 0.429 and it exceeds free space and the BRIDGE COLLAPSES! :)
The M35 2½-ton cargo truck is a long-lived 2½-ton 6x6 cargo truck initially used by the United States Army and subsequently utilized by many nations around the world. Over time it evolved into a family of specialized vehicles. It would not only inherit the World War II GMC CCKW's famous "Deuce and a Half" nickname but forge its own legacy.