A weather balloon carries a mercury barometer in order to determine altitude as a function of flight time. At a particular moment, the barometer gives a reading of 460 mm. How high (in meters) is the balloon above standard sea level? (Assume mercury has a density of 13,600 $\displaystyle \frac{\text{kg}}{\text{m}^3}$
, and approximate that dry air at any elevation has a constant density of 0.9
$\displaystyle \frac{\text{kg}}{\text{m}^3}$
.)

m