Question

Determine the mass of the petcock of a pressure cooker whose operating pressure is 102 kPa gauge and has an opening cross-sectional area of 4 mm². Assume an atmospheric pressure of 101 kPa.

Answer 1

The mass of the petcock is approximately 0.408 grams.

Step-by-step explanation:

The mass of the petcock of a pressure cooker can be determined using the formula:

mass = pressure * area / gravitational acceleration

First, we need to convert the pressure from kPa gauge to Pa absolute. To do this, we subtract the atmospheric pressure from the operating pressure:

pressure = 102 kPa - 101 kPa = 1 kPa = 1000 Pa

Next, we convert the area from mm² to m²:

area = 4 mm² = 4 * 10^-6 m²

Finally, we can calculate the mass:

mass = 1000 Pa * 4 * 10^-6 m² / 9.81 m/s² = 0.000408 kg = 0.408 g