Air is removed from a rigid display chamber by a pump. One side of the chamber is a flat rectangular panel measuring 24 cm by 15 cm.
The air pressure inside the chamber is 28 000 Pa28\,000\ \text{Pa}28000 Pa. The atmospheric pressure outside the chamber is 96 000 Pa96\,000\ \text{Pa}96000 Pa.
A valve is opened so that air enters the chamber. The pressure inside the chamber rises to 53 000 Pa53\,000\ \text{Pa}53000 Pa while the atmospheric pressure outside remains constant.
Explain how the resultant force on the panel changes as air enters the chamber.
The chamber is operated with the air pressure inside at 28 000 Pa28\,000\ \text{Pa}28000 Pa.
The fastenings holding the panel fail if the resultant force on the panel is greater than 2.7 kN2.7\ \text{kN}2.7 kN.
Calculate the greatest atmospheric pressure outside the chamber at which the fastenings will not fail.
132 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.