1. **Problem:** A vacuum gauge reads 30 kPa and the barometric pressure is 755 mm Hg. Find the absolute pressure in the tank. 2. **Formula:** Absolute pressure $P_{abs} = P_{barometric} - P_{vacuum}$ for vacuum gauges. 3. **Convert barometric pressure:** 1 mm Hg = 133.322 Pa, so $$P_{barometric} = 755 \times 133.322 = 100,666.31\,Pa = 100.66631\,kPa$$ 4. **Calculate absolute pressure:** $$P_{abs} = 100.66631 - 30 = 70.66631\,kPa$$ 5. **Answer:** The absolute pressure in the tank is approximately $70.67\,kPa$. --- 2. **Problem:** A vacuum gauge reads 5.4 psi and barometric pressure is 28.5 in Hg. Find absolute pressure. 3. **Formula:** $P_{abs} = P_{barometric} - P_{vacuum}$. 4. **Convert barometric pressure:** 1 in Hg = 0.491154 psi, so $$P_{barometric} = 28.5 \times 0.491154 = 14.0005\,psi$$ 5. **Calculate absolute pressure:** $$P_{abs} = 14.0005 - 5.4 = 8.6005\,psi$$ 6. **Answer:** The absolute pressure in the tank is approximately $8.60\,psi$. --- 3. **Problem:** A pressure gauge reads 3.5 bars and barometric pressure is 75 cm Hg. Find absolute pressure. 4. **Formula:** For pressure gauge, absolute pressure $P_{abs} = P_{barometric} + P_{gauge}$. 5. **Convert barometric pressure:** 1 cm Hg = 1333.22 Pa = 0.0133322 bar, so $$P_{barometric} = 75 \times 0.0133322 = 1.0\,bar$$ 6. **Calculate absolute pressure:** $$P_{abs} = 1.0 + 3.5 = 4.5\,bar$$ 7. **Answer:** The absolute pressure in the tank is $4.5\,bar$.