Q1. Crew members attempt to escape from a damaged submarine 77.9m below the surface. What force must be applied to a pop-out hatch, which is 1.38m by 0.692m, to push it out at that depth? Suppose that the density of the ocean water is 1024 kg/m3 and the internal air pressure is at 1.00 atm.

Q2. A 9.40kg projectile is fired vertically upward. Air drag decreases the mechanical energy of the projectile-Earth system by 69.5kJ throughout the projectile's ascent. How much higher would the projectile have gone were air drag negligible?