An archaeologist is investigating a shipwreck and discovers a wooden box on the seabed.
Fig. 4.1
The dimensions of the lid of the box are 1.2 m by 0.80 m and the pressure of the atmosphere
is 1.0\times 10^(5)Pa. The lid is 15 m below the surface of the sea.
(a) The density of sea-water is 1020k(g)/(m^(3)).
Calculate
(i) the pressure on the lid of the box due to the sea-water, (ii) the total pressure on the lid,
pressure =
(iii) the downward force that the total pressure produces on the lid.
force =
(b) The force needed to open the lid is not equal to the value calculated in (a)(iii). (b) The force needed to open the lid is not equal to the value calculated in (a)(iii).
Suggest two reasons for this.