The pressure at the depth 11 km below sea level can be
calculated using
P=ρgh
P is pressure, ρ is the density of the fluid; g is the
gravitational constant, h is the height from the surface, or depth that the
object is submerged.
P = ( 1000 kg/ m3) ( 9.81 m.s2)( 11 000m) + 1 atm
P = 107,910,000 pa ( 1 atm/ 101 325 Pa) + 1 atm = 1066 atm
The ball should take twice as long to return to its original position as it took to reach its maximum height, so it should return to its original position at .
