A lid is put on a box that is 18 cm long,17 cm wide, and 8.0 cm tall and the box is then evacuated until its inner pressure is 8.7 104 Pa.
a) How much force is required to lift the lidat sea level?
b) How much force is required to lift the lid in Denver on a daywhen the atmospheric pressure is 67.5 kPa (2/3 the value at sealevel)?