A diver is 12 m below the surface of the sea. The density of sea water is 1030 kg/m³ and atmospheric pressure is 100 000 Pa.
(a) Calculate the pressure on the diver caused by the sea water. Use $g = 10\ \text{N/kg}$. [2]
(b) Calculate the total pressure on the diver. [1]
(c) The diver turns to face a different direction at the same depth. State what happens to the pressure acting on the diver's face mask. [1]
- (a) substitution: pressure difference = 12 × 1030 × 10(1)
- (a) evaluation: 123 600 Pa; accept 124 000 Pa, 124 kPa or $1.2 \times 10^{5}$ Pa; correct answer with no working scores 2(1)
- (b) 223 600 Pa; accept 224 kPa or $2.2 \times 10^{5}$ Pa; allow 100 000 + their (a)(1)
- (c) stays the same / does not change; accept 'pressure acts equally in all directions'; reject increases / decreases(1)
- Answer: (a) 123 600 Pa (b) 223 600 Pa (c) stays the same
- Examiner tip: Read carefully whether the question wants the pressure due to the water alone or the total pressure including the atmosphere.