The Physics Student

One day a science teacher gives his student the following problem.

You need to determine the height of a building and that you have a barometer.

Having just learned about barometric pressure, most of the students took the path of solving the problem by taking the barometric pressure at the base of the building and taking the pressure at the top and using the difference to determine the height of the building.

BUT one student decides to suggest the path less traveled –

Instead answering that while using the barometric pressure differential would provide an approximation of the building height a more accurate determination could be made by taking the barometer to the top of the building and dropping it and timing how long to takes to smash into the ground. Taking the time and using the formula


where a is acceleration due to gravity of 9.8m/s^2 and t is the time in seconds and d is the height of the building in meters. To get the building height in feet you would use 32f/s^2 as a.

BUT the student went on with the answer saying that the problem with this solution is that it would waste a perfectly nice barometer and instead suggested that they take the barometer to the building superintendent and say “we’ll  give  you  this  nice  new  barometer  if  you  will  just  tell  us  how  tall  your  building  is.” thereby getting the answer and not destroying the barometer.