Two items of equipment are positioned on a theatre stage.
| item | total normal force on the stage | supports in contact with the stage | contact area of each support |
|---|---|---|---|
| lighting tower | 7200 N | 6 base plates | 0.015 m2 |
| mobile sound-equipment case | 900 N | 4 castors | 3.0 cm2 |
Use 1 m2=10 000 cm21\ \text{m}^{2}=10\,000\ \text{cm}^{2}1 m2=10000 cm2.
Calculate the pressure that the lighting tower exerts on the stage.
Calculate the pressure that the mobile sound-equipment case exerts on the stage.
Protective sheets will be put beneath whichever item exerts the greater pressure. The stage manager chooses the lighting tower because it produces the greater normal force.
Explain why the calculated pressures do not support this choice.
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.