Browse Teasers
Search Teasers

## A Truck and a Bridge

Science brain teasers require understanding of the physical or biological world and the laws that govern it.

 Puzzle ID: #374 Fun: (2.45) Difficulty: (1.63) Category: Science Submitted By: JoeyChavez

A truck comes to a 1000 ft. long bridge and stops right before going on to it to read a sign. The sign says that the maximum weight the bridge can hold is 4 tons, which is the exact weight of the truck. So the truck starts going on the bridge. About halfway over the bridge a little bird lands on the top of the truck. Does the bridge break?

## What Next?

See another brain teaser just like this one...

Or, just get a random brain teaser

If you become a registered user you can vote on this brain teaser, keep track of
which ones you have seen, and even make your own.

 blazeoner Jun 09, 2001 What about the weight of the truck driver? KmartSmile Jul 16, 2001 what about the drivers weight? Pongalopete Sep 07, 2001 Ditto what about the driver's weight was it included? randyeatmon Oct 06, 2001 "Gas" and fuel are commonly interchangeable. If the fuel were Diesel and the engine in good condition then it would be an arguable proposition. The "Bird" could also have been a well fed Eagle. Too vague. (user deleted) Nov 15, 2001 that is one innefficient truck to use a birds weight if fuel in 500ft (user deleted) Feb 22, 2002 I am sure when engineers are designing bridges they take into consideration exrta weight. And anyway birds don't weigh that much... bluetwo May 29, 2002 elsie is absolutely correct. the engineers build in a certain margin of safety in the design. just because a bridge is rated to 4000 lbs does not mean that it will crumble to the ground when 4100 lbs of force is applied. it is, however, a "safe" figure. by the same token, rooms can hold more than their stated max capacity, but it is due to safety concerns in the event of an emergency that those capacities are stated. jonnyonline Jan 24, 2003 what if the bird landed on the truck, latched it's claws around a part of the roof and started flapping upwards, then its weight would be negligible. Mogmatt16 Jun 29, 2004 no, becuase then the bird would be pushing air down equal to it's weight. TehIgnored Mar 03, 2006 When in danger or in doubt, run in circles scream and shout.... and no...im sorry but this is a VERY weak riddle.... Crazycriely Mar 25, 2006 well i said no, but i dont think the gas or the bird would be very significant weight so i dont think it would break. Vigo95 Mar 25, 2006 i agree crazycriely ! Atropus Apr 05, 2006 I'm with elsie on that one... It's like those elevators that have a limit of 9 people.. there is a margin of error built into any structure that people want to keep up. Redundancy is one of the fundamental principles in architecture. calmsavior May 10, 2006 whys everyone talking about the weight of the driver? Mellew Jul 30, 2006 but what if another car is on the bridge also?? cyberstar5150 Aug 04, 2006 Yeah... if you're using a bird's weight in gas to go that far, you're in trouble. The true reason it would be okay is because engineers have a factor of safety built in... and would NEVER put a sign up that says the absolute maximum or people like this guy would try to max out and destroy the bridge. cyberstar5150 Aug 04, 2006 For those of you who aren't engineers and don't know what factor of safety is: Factor of safety takes into account the worst case scenario for that bridge (say the worst case is 1000 lbs) and makes it stronger to avoid having it break (say they make it able to tolerate 1500). The factor of safety for such a bridge is 1.5. rrn0rrnrrnY Sep 08, 2006 simple teaser, simple answer:No LeafFan4life Mar 02, 2007 i got answer no but for wrong reason here is my reasoning: Most signs such as elevators but the maximum weight it can with stand on it but they usually put less than it actually is just incase so if it said can hold 1200pounds it can probably hold more than that but just for safety they put less. deadsnakebiting Mar 14, 2007 Before looking at the Answer or the other Comments, "I swear no peeking - I'm out here on a limb, gang;" no, the bridge will not break. Ratings are set at a weight that does not come close to the actual limit (maybe 15-20% less) for exactly these types of situations. Now, I will go look at the answer and see how I did! deadsnakebiting Mar 14, 2007 PS. Just a follow up... the given answer shows a little thought - but the rating / actual maximum weight still stands - look it up! Otherwise lots of bridges would fail because most truckers use the SWAG method to determine their weight. SWAG = Scientific Wild-Ass Guess!