A thin, rigid, spherical shell with a mass of 6.00 kg and diameter of 0.400 m is filled with helium at 0 degrees celsius and 1 atm pressure.

A thin, rigid, spherical shell with a mass of 6.00 kg and diameter of 0.400 m is filled with helium at 0 degrees celsius and 1 atm pressure. It is then released from rest on the bottom of a pool of water that is 6.00 m deep.A.) determine the upward acceleration of the shell.B.) How long will it take for the top of the shell to reach the surface? disregard the frictional effects.