A lid is put on a box that is 11 cm long, 11 cm wide, and 8.0 cm tall and the box is then evacuated until its inner pressure is 4.2 104 Pa.
(a) How much force is required to lift the lid at sea level? N
(b) How much force is required to lift the lid in Denver on a day when the atmospheric pressure is 67.5 kPa (2/3 the value at sea level)? N